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This paper evaluated a novel diagnostic test designed for early detection of breast cancer. This test was specifically designed for use in low resource settings, where the incidence of breast cancer is rising but is not matched by a similar increase in access to diagnostic tools. What was interesting about the device is that is performed at fairly high sensitivity and specificity levels when compared to the combined use of mammography and ultrasound. However, the device was not tested in terms of cancer detection, but was tested in terms of accurately identifying patients needing a follow up. More research should be done to further this device's use, but for now it seems to be a good device for early detection and screening efforts.

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American Association for Cancer Research

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Maurício M Costa, Anne F Rositch, Fernanda PA Pereira, Hildoberto C de Oliveira, Carolina F de Oliveira, Nilson Gomes, Flávia PPL Lopes; Abstract P1-01-06: Diagnostic accuracy of a novel palpation device to improve early detection of breast cancer in low-resource settings. 15 February 2020; 80 (4_Supplement): P1-01-06. https://doi.org/10.1158/1538-7445.SABCS19-P1-01-06

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Abstract P1-01-06: Diagnostic accuracy of a novel palpation device to improve early detection of breast cancer in low-resource settings

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Abstract. Background and objectives: As the most commonly diagnosed cancer in women, breast cancer is projected to reach 1 million cases per year by 2020 in LMICs alone. Although incidence continues to increase in low- to middle-income countries, access to early detection in these high burden areas remain limited, in part due to lack of low-cost efficacious tools where mammography isn't feasible.

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Pros of Rapid Diagnostic Tests are that they are much faster and cheaper than other existing diagnostics. Additionally, with the correct design, they are much easier to use and can often be used by patients themselves (as we have seen with the COVID-19 RDTs). However, the primary tradeoff is test performance, with the tests often having much lower sensitivity than other diagnostics, and a lack of qualitative results which means that limited information is provided to a user.

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It is important to think about all of the stake holders throughout the design process so that the timeline of your design, testing, and distribution is as short and efficient as possible. If you consider the qualifications of the person using your device, who you device will be used on, the maintenance requirements, and the production costs of the device at the very beginning you wont have to go back and make as many revisions to your product. This will save overall time and money.

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Dr. Locke focuses her research in point of care diagnostics, using optical biosensing to address issues within POC diagnostics for low resource settings in a variety of disease states.

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Stakeholders are ultimately the people or organizations that are providing funding and design requirements for any given project. They are the ones that determine what is important, needed, necessary, and extraneous in any new design. Additionally, stakeholders come from a variety of areas, and includes the actual patients and physicians using the device. Without considering all stakeholders involved, a device cannot adequately solve an issue at hand.

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Dr. Locke's research focus is on optical biosensing and fluorescence sensing technologies that will allow for easier and less invasive diagnosing of diseases such as diabetes, cancer, oral cancer, premature birth, etc.

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The Bulo Breath Analysis device is a personalized breathing training assistant that monitors the health of the users lungs. The feature I find most interesting about this device is that a uniform and hand held device is able to record the users previous history of breath capacity and compare current lung health to give the users overall lung health. In addition, to the form factor and abilities I find it interesting that the device also gives the user personalized breathing exercises to improve lung health.

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Each stakeholder holds a key role in the product ultimately being successful. Certain stakeholders have the capability of preventing the product from ever getting to market, while others determine whether the device will be a complete failure when it reaches the market. Taking into account all of these opinions in the design process will hopefully lead to the most support possible for your device, which will lead to a market success and legal approval for use. Failure to take into account their opinions could result in ultimate failure, which means a waste of time and money that could have been avoided.

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Dr. Locke's research centers on increasing access to healthcare in low resource areas. One way she's looked to do this is through point-of-care diagnosis with optical biosensing. The specific device she discussed in class was a wrist implant that would use a watch to take glucose readings for patients with diabetes to avoid finger pricking, but also address the short life span of current continuous glucose monitoring systems.

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The neoGuard is a wireless device that attaches to a patient's forehead to continuously measure oxygen saturation, pulse, respiratory rate, and temperature. It was designed with the feedback from 400+ health care workers primarily in East Africa to be used in low resource settings. The most interesting thing about this device for me is that it uses the forehead as the measurement location. While I have of course heard of monitors for all of these vitals, I usually hear about the sensors being on the arms, hands, feet, and chests. This is the first such device I've heard that uses the forehead, but it is also the first time I have heard of temperature being lumped in with these continuously monitored vital stats, which may be a factor.

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Assumpta Nantume 1*,

Teresa Cauvel 1,

Matthew Tomback 1,

Ryan Kilpatrick 2,

Bushra Afzal 2 and

Noah Kiwanuka 3

Neopenda, PBC, Chicago, IL, United States

Floating Children's Hospital at Tufts Medical Center, Boston, MA, United States

Department of Biostatistics and Epidemiology, Makerere University School of Public Health, Kampala, Uganda

The neoGuard™ technology is a wireless wearable vital signs monitor attached to a patient's forehead to continuously measure oxygen saturation, pulse rate, respiratory rate and temperature. Developed with feedback from more than 400 health workers, primarily in East Africa, the product has been designed to meet the unique constraints of low-resource settings. This perspective piece by the innovators of neoGuard™ and some of their key partners examines the complicated journey of taking a medical technology from concept through clinical validation and finally to market. By shedding light on some of the most critical steps and common challenges encountered along the pathway to commercialization, the authors hope that their experiences will provide some valuable insights to other aspiring innovators in this space.

Introduction

In the aftermath of the COVID-19 pandemic, digital health products have gained increasingly wide appeal for the delivery of health services to patients in high-income and low-income settings alike. As researchers, clinicians and policy makers rallied to optimize patient care and alleviate the burden on health facilities and hospital staff at the height of the pandemic, global efforts to leverage digital health solutions became more invigorated than ever before ( 1- 3).

Yet despite the recent uptick in digital health interest, innovators still struggle to navigate the existing ecosystem and face significant barriers to transitioning their ideas from concept to market ( 4), particularly in low-and-middle-income countries (LMICs) where the health technology space is maturing at a slower pace ( 5). At the same time, there is a tremendous opportunity for innovators worldwide to seize this unprecedented moment and capitalize on these recent digital health gains. In this perspective piece, the team behind the wireless vital signs monitor, neoGuard, reflects on its journey creating and commercializing a health technology product for patients in low-resource settings. By examining our own experience, we aim to offer some useful insights on potential pitfalls in medical device innovation and how to successfully navigate the current digital health ecosystem.

neoGuard Origin Story

The idea for Neopenda's neoGuard device started with a mission of addressing an unmet need for vital signs monitoring solutions for newborns in low resource settings. Through a series of formal and informal needs assessments, we quickly established that conventional vital sign monitoring equipment were unable to meet the constraints of low-resource settings due to (i) the high cost of initial purchase and maintenance, (ii) infrastructure challenges such as space limitations and power outages, and (iii) their reliance on single-use accessories which are not always readily available.

Designing a product to adequately meet our user's needs while overcoming these salient challenges became the focus of our innovation efforts. Like many medical technologies and digital health solutions, Neopenda started in the academic world as a design project by a team of graduate biomedical engineering students. Driven by the mission and neoGuard's potential for positive impact on healthcare in underserved communities, we transitioned from academia to a startup venture. After consulting with more than 400 health workers, primarily in Uganda, we were able to design an affordable, reusable, wearable, multi-parameter vital sign measurement device over the course of 4 years.

The neoGuard device continuously measures temperature (temp), blood oxygen saturation (SpO 2), pulse rate (PR) and respiratory rate (RR), and wirelessly transmits readings to a central dashboard (NeoMonitor app) that is hosted on a tablet ( Figure 1). The system provides real-time visual and audio alerts whenever a patient's vital sign measurements fall outside preset upper or lower limits. The NeoMonitor app can display data from up to 15 devices at a time, making it an ideal tool to simultaneously monitor multiple patients in health facilities with very low nurse-to-patient ratios.

Figure 1. The neoGuard V1.0 vital signs monitoring system.

Early Testing

Between November 2018 and November 2019, we conducted two IRB-approved pilot studies that aimed to (i) evaluate the preliminary safety of neoGuard by describing and quantifying any adverse events, (ii) evaluate the ability of the device sensors to detect high fidelity PPG (photoplethysmogram) waveform signals from the newborns' capillaries, and (iii) assess the preliminary concordance of neoGuard measurements with reference measurements from a standard-of-care/conventional vital signs monitor. The pilot studies involved 22 stable newborns (aged <28 days) at Tufts Children's Hospital (formerly Floating Hospital for Children) at Tufts Medical Center in Boston, Massachusetts and 27 healthy newborns and infants (aged <16 weeks) at Jinja Regional Referral Hospital (Jinja RRH) in Jinja, Uganda. Regulatory approvals were obtained from the Tufts Health Sciences Campus Institutional Review Board for the Tufts study, and from the Makerere University School of Public Health (MakSPH) Higher Degrees Research and Ethics Committee and the Uganda National Council of Science of Technology for the Jinja study.

Results from both studies showed that the neoGuard device demonstrated comparable safety to standard-of-care equipment (with no adverse events recorded from either system) and sufficient signal quality to register changes in the PPG waveforms. However, accuracy of vital sign measurements was variable from patient to patient, showed high sensitivity to motion artifacts and device placement, and was further impacted by the large size of the prototype hardware device and inadequate design of the headband. Through an iterative design process, we recalibrated sensor settings and refined the vital signs algorithms to reduce noise (unruly signals) from these sources until we attained robust performance for the measurement of temperature, pulse rate, blood oxygen saturation, and respiratory rate. The hardware of the neoGuard device was also optimized, including reduction of the size by over 60%.

The design process involved three main hardware iterations, culminating in the first production release of the device, neoGuard wearable device ( Figure 2). Feedback from clinicians involved in the Tufts and Jinja studies was also invaluable for the improvement of the neoGuard headband design. The band evolved from a disposable fabric band, to a two-piece silicone band, to an adjustable single-piece reusable silicone band ( Figure 3). Later, an extender strap was created to enable the headband to fit adult patients as well. Being responsive to stakeholder feedback throughout the development process is crucial to creating a product that will be readily adopted by end users. Without this iterative, collaborative early phase, neoGuard would have performed less successfully in the human factors usability engineering studies and post-market clinical follow-up studies later on.

Figure 2. Prototypes of neoGuard hardware versions v1.0 (left), v2.2 (center), and v3.0 (right).

Figure 3. Sampling of neoGuard headband design concepts.

In addition to performance testing, early research on neoGuard also explored human factors and usability engineering (HFUE). HFUE, an essential component of the medical device design and development process, involves bringing users and stakeholders into the design process to make sure that the solution being created will meet their needs and be usable for them. Data on HFUE was collected through training workshops, simulation exercises and user surveys, and interviews. This HFUE data drives many design decisions and product requirements. In total, ~70 health staff participated in the formative and summative assessments for HFUE. An additional 330 health staff constituted the voice-of-customer (VOC) research.

Clinical Validation Studies

To comply with ISO/IEC standards for pulse oximetry ( 6) and temperature monitoring ( 7) across the appropriate measurement ranges, final accuracy validation was conducted at Clinimark Laboratories in Louisville, CO, USA and the Hypoxia Lab at University of California San Francisco (UCSF). All testing was conducted with production-equivalent units, that is, the "final" product or equivalent. Testing on human subjects was conducted under IRB approvals from Clinimark Laboratories and UCSF.

We attained robustperformance for measurement of temperature (range 30-40°C, accuracy ±0.3°C, over a variety of ambient conditions), pulse rate [range 45-205 beats per min (bpm), accuracy ±3 bpm], blood oxygen saturation (range 70-100%, accuracy ±4%), and respiratory rate [range 5-30 breaths per min (brpm), ±5 brpm]; meeting the accuracy requirements of the applicable ISO/IEC standards ( Table 1).

Table 1. Summary of clinical validation study results.

Regulatory Approval

As a medical device used in the clinical environment, neoGuard is subject to rigorous regulation in all markets to ensure it is safe and effective. To create a medical device meeting the standards for commercial, clinical use, a medical device company must implement a design control process, and quality management system in compliance with internationally recognized standards such as ISO 13485 ( 8). Early in the design and development process the applicable regulatory standards for the product should be identified and incorporated into the product requirements. If the design team does not have regulatory or quality expertise, external consultants are necessary. Neopenda began contracting regulatory and quality expertise in year 2.

In accordance with the CE mark classification guidelines, we categorized the neoGuard product as a class IIb medical device and pursued the CE marking regulatory pathway (route 1) to demonstrate compliance with the European Union Medical Device Regulation (EU MDR) ( 9). Under this process, we underwent a full quality assurance audit by a notified body and obtained ISO 13485:2016 certification for our quality management system. Next, we submitted a technical file for the neoGuard product to the same notified body. After review of the technical file and audits of both Neopenda and our critical sub-contractors, the EU certificate was granted. Then the CE mark and notified body number are affixed to the neoGuard product and a Declaration of Conformity is ratified.

CE mark certification is recognized by most medical device regulators in our target countries ( 10) and will allow us to bring the neoGuard product to market efficiently. In addition to CE mark, many countries also require appointment of a local agent/representative to complete product registration with the appropriate regulatory body and obtain final import and marketing clearance.

Commercialization Efforts

To reach most hospitals in emerging markets, medical equipment is often procured through a wholesale distributor. In Kenya and Uganda, where Neopenda has launched neoGuard, we have worked closely with a local authorized representative and distributor to register the neoGuard product and obtain import clearance from the Kenya Pharmacy and Poisons Board and the National Drug Authority, respectively.

Successful adoption of a new technology extends beyond the design of a product, and into appropriate implementation. This includes an emphasis on user training, installation, preventative and reactive maintenance, and adequate sales and marketing efforts. Our immediate strategy consists of leveraging the expertise of local distributors to implement neoGuard. This model provides a scalable approach to penetrating new markets without having to build a large sales/marketing team in every country we enter into. Similarly, on the production side, we have outsourced manufacturing of the neoGuard devices to a contract manufacturer with the infrastructure, supplier network and quality management system necessary to mass produce, package, and deliver thousands of devices to our in-country distributors efficiently and cost-effectively.

Post-Market Performance Evaluation

Under the EU MDR requirements, it is recommended that medical device innovators complete at least one post-market clinical follow-up (PMCF) study after launching their product. In addition to the PMCF study, innovators are also encouraged to initiate broader scope evaluations encompassing a larger number of users/patients in order to supplement their pre-market approval findings on the safety and effectiveness of the approved device. Clinical data from post-market studies are not only valuable for post-market surveillance. These studies maybe referenced in updating claims on device efficacy, expanding the product's indications for use, as well as assessing market acceptance and uptake ( 11).

Neopenda has plans to implement at least six post-market research studies on the neoGuard product, including short-term implementation feasibility studies in Uganda, Kenya, Tanzania, Nigeria, and Mali, and a medium-to-long term clinical impact and cost-effectiveness study in Kenya. At least two of the planned studies will be led by independent non-profit partners in our target countries.

In parallel with our formal research, we will also conduct routine monitoring and evaluation where we aim to (i) capture monthly or quarterly performance metrics through the neoGuard backend data repository and (ii) gather additional user feedback through routine surveys with early adopters.

Potential Pitfalls and Lessons Learned

Pre-mature Product Testing

While there is an understandable temptation for innovators to begin testing their products as soon as they have a functional prototype, clinical research is an expensive endeavor, and even small scope pilot studies have considerable time and cost implications. It is important to plan out the phases of testing that will be needed, and to first generate sufficient evidence that your product will perform as intended before you put it to the test in a formal clinical setting. Where possible, this can be achieved through bench top testing in a lab setting; for instance, with the neoGuard product, we were able to employ a pulse rate simulator and water bath to test for pulse rate and temperature, respectively, before further testing on human subjects. It is also important to note that significant product modifications may arise from the early testing phase while you conduct thorough bench testing and gather user feedback. In some cases, it might require more than one pilot study before you are fully confident in initiating your design freeze. The "final" clinical validation study(s) must be conducted after design freeze, with the final or production-equivalent product. While the introduction of new devices requires testing within the target market, one bottleneck that innovators are likely to run into in LMICs is the limited access to gold-standard equipment or measurement techniques. For instance, our research team had intended to use end tidal carbon dioxide (EtCO 2) as a comparison method for the respiratory rate measurement by neoGuard; however, EtCO 2 monitors were not readily available in Uganda, so we opted to perform this component of testing with a US-based researched partner. As far as possible, innovators in low-resource settings should leverage partnerships with institutions that may have better access to the resources they need to perfect and test their early prototypes. This will significantly help reduce the risk of testing a product in-field before it is fully functional or ready to be tested by users. That said, the importance of early product testing in target markets should not be overlooked however complicated the process may be. Environmental considerations such as temperature, humidity, or the layout of health facilities can have a significant impact in the performance of your technology, and gathering this data early on will enable innovators to respond proactively.

Insufficient Preparation for Quality Management and Regulatory Affairs

A medical device should be designed within the existing regulatory framework and quality requirements. Innovators should know the product specifications that are deemed acceptable in clinical practice, as well as any electrical safety, electromagnetic compatibility (EMC), or radio frequency emissions standards pertaining to their product. Your target parameters and corresponding validation tests needed should be clearly defined in your technical file. Conduct extensive research on the regulatory pathway you are pursuing and engage experienced personnel and/or consultants to help you navigate any policy hurdles. It is important to be familiar with the IRB process and documentation that may be necessary. However, the IRB process for research involving medical devices is often not well-defined and is still evolving in many low-resource settings. Having IRB-approval from a US-based institute or other country where medical device studies occur more frequently may help strengthen your efforts for research clearance with a local IRB. In many cases, local IRBs may not have the necessary medical device expertise to adequately assess the risks and benefits or your research, so providing evidence of review by another IRB can help quail some of their concerns. In the same regard, selection of an IRB committee with relevant experience reviewing medical device research is critical. Some of the essential documents you should prepare to include in your research application are: a detailed protocol, operator's manual, investigator's brochure, informed consent forms, and preliminary safety and efficacy data. For devices that are above non-significant risk, which do not pose significant risk to human subjects, pre-approval and registration with the country's medical product regulatory agency may be necessary. It is important to be familiar with secure data ownership and security requirements to protect subject privacy and health information. After initial IRB approval, studies will be subject to regular reviews and any significant protocol or device changes will require IRB approval. Having the right expertise on your team will help limit the amount of time it takes to reach your next milestone. In preparing your budget, anticipate that the quality and regulatory stage will almost definitely cost more and take longer than you project.

Applying Inappropriate or Impractical Research Methods

Think carefully about your choice of research methods and consider your justification for why your methodology is appropriate. The nature of a medical device, the context in which it is applied, and cost implications can often limit the study design to more simplistic single-arm trials. Regardless of the underlying reasons, it is important to reflect on the limitations of any study design. Seek out opportunities to collaborate with research partners from academia or non-profits who are working to address similar challenges. Collaborators may provide expert knowledge and external insights on the feasibility of your product.

Ensure that your data collection methods and data analysis approach are equally robust. Where possible, validate or pre-test your research tools for clarity, face validity, and content validity. Provide relevant training and guidance to study personnel involved in data collection. Research objectives should place equal emphasis on both the quantitative performance metrics and the qualitative user experience. A comprehensive analytical framework should also take into consideration the role of social forces (e.g., trust in medical authorities, myths around technologies) and how the requirements or expectations of a medical product may vary in different clinical situations and cultures. For instance, many users of the neoGuard technology shared concerns that the patients caretakers or family may feel anxious seeing a device affixed to a patients forehead, as this was an unusual attachment area for a vital sign monitor. However, when it came to actual implementation of the technology, we observed that this anxiety was not as prevalent as we had imagined. Patients' caretakers and family demonstrated a high level of trust in the medical staff attending to their patient, and the medical staff reported that they had no trouble explaining the role of the technology and responding to any questions or concerns that patients or caretakers harbored. Through user surveys and caretaker interviews, we concluded that the unusual placement of neoGuard on the forehead of the patient would be acceptable.

Finally, innovators must consider if the evidence they are generating will satisfy the requirements of their target audience. For instance, while local stakeholders might appreciate results from a familiar clinical setting within the target market, regulators will more often be inclined to accept performance findings from studies conducted in a more controlled lab setting or by an accredited third party with the ability to test your device against acceptable standards. As discussed previously, access to the acceptable standards maybe more limited in low-resource environments.

Lack of Emphasis on Human Factors and Usability Engineering

Focusing heavily on the performance aspects of the technology without considering how human factors can lead to user errors and how this might impact the safety and effectiveness of the product can yield unfavorable results. At Neopenda, we believe strongly in the theory of human-centered design, and we leverage VOC and HFUE data to drive design decisions. This is more important than ever for products intended for low-resource environments; sustainability of the design is essential, and the product must be long-lasting and easy to implement and use. When conducting VOC research, it is necessary to capture perspectives from all categories of users. For instance, for a phone-based application, the ability to correctly use the technology will be influence by factors such as age, smart-phone ownership, and/or experience and computer literacy. These factors will vary not only from person to person but from location to location. If a technology s intended to be implemented broadly in rural and urban facilities alike, then the VOC and HFUE data should be collected from all relevant settings.

Elements of VOC and HFUE are often conducted early on in the product development lifecycle. As a result, they are poorly documented and loosely structured. It is crucial to create some sort of guiding framework for your VOC and HFUE, however, flexible and imperfect it might be. For instance, if user testing in a real setting is not immediately practical, then consider how you might best simulate a testing environment or script hypothetical scenarios for users to respond to. To best understand what challenges or barriers users may encounter in using your technology, you want to recreate the same user experience as closely as possible to measure any recurrent errors. In a sense, your goal is to approach the user testing like a controlled experiment, leaving room for variability only at the user level. On the subject of documentation, innovators should record these early efforts in real-time and incorporate them in a Design History File (DHF). A DHF should systematically encapsulate every critical design change and all relevant feedback or data that helped inform that change. Tracing this pathway to the final product is important not only from a regulatory perspective, but also to remind the innovator of why certain design choices were made in case future product changes threaten to impact them. For Neopenda, our approach to VOC and HFUE was not clearly defined when we started; in fact, it took months of retrospective analysis and piecing together various sources of data gathered over the course of 3 years to map out how human factors had been accounted for in relevant design features.

Inadequate Stakeholder Engagement

Engagement with key stakeholders is required throughout the medical device life cycle. Failing to adequately consult the full breadth of potential stakeholders may have negative effects such as costing the innovator additional time and finances if any important early processes are skipped. Buy-in from various stakeholders-users, ministries of health, international non-governmental organizations, implementation partners, and hospital administrators, amongst many others-is essential to success. Getting buy-in can be challenging particularly at the early stages of development, and building relationships takes time. Even once a stakeholder or partner is engaged, management of the partner and regular communication is key to sustaining their interest and support. Setting clear expectations of goals, responsibilities, timelines, and financial responsibilities is essential for continued engagement. While synergizing efforts between stakeholders can yield more efficient and effective results, managing stakeholders can become a time-consuming and challenging task if expectations are not set in advance and maintained throughout the relationship by both parties. Cultural differences will also influence how well stakeholders respond to your medical product and how your motivations are perceived. Foreign innovators coming into low-resource settings with only minimal experience in the subject they are addressing are likely to be met with far greater skepticism than innovators who have a solid foundation working in their target communities. This is why innovation hubs cropping from familiar entities like non-profits or academia appear to have a more positive experience implementing new products or strategies in LMICs than traditional startups operating on their own. To add to that, however well-meaning an innovator's intentions may be, it is difficult for stakeholders to ignore the commercial incentive behind an enterprise. In this regard, non-profit and academic actors tend to wield more power and influence in the innovation space in LMICs because they are generally perceived to be more altruistic than traditional startups. This is another reason why individual innovators should consider collaborating or having their products independently evaluated by reputable non-profit or academic partners. Working with stakeholders who have no commercial conflicts and are able to speak independently regarding the performance of a product will give stronger credibility to an innovator's claims.

Unreliable Pre-market and Post-market Revenue Streams

Taking a medical device from idea to commercialization is an arduous and iterative process that requires significant upfront capital. Innovators may elect to receive funding through non-dilutive capital (e.g., grants or competitions) and/or dilutive capital (e.g., through accelerators or investors), and the type of capital received is likely to evolve as the company matures. Planning and budgeting for the full life cycle of a medical device is a challenging but important task; many innovators fail to receive enough funding to get through the life cycle. Unlike many software or service provider startups, medical device development requires significant upfront capital. The capital is required to fund R&D efforts such as prototyping, field testing, clinical validation, scale-up to manufacturing (e.g., tooling costs to produce the device at scale), general operating expenses such as salary, rent, and legal fees, and regulatory and quality activities. Early-stage medical device innovators are often perceived as a high-risk investment due to the length of time it takes to get a medical device to market, and the upfront capital required before generating revenue. Defining a roadmap and associated budget can demonstrate an innovator's expertise in medical device development. Execution of the roadmap with acceptable pivots but within the planned budget will de-risk the company as innovators progress with their roadmap.

Beyond the initial financing for product development, innovators should have a clear understanding of the business environment(s) they are entering into and how long it may take before they are able to generate a steady stream of revenue. Evidence that there is a need for a product does not guarantee that the market will readily take up the product once it is available. In pursuing new leads, innovators should be conscious not to overestimate their market size as well as their customer's willingness and ability to pay. To establish some initial brand recognition and help kick-start market penetration for your technology, it is worthwhile to approach potential consumers or customer segments early on in the product development process to understand not only how they respond to your product, but how they evaluate and make purchasing decisions. In the buildup to the launch of the neoGuard product, Neopenda completed more than 80 hospital visits, and engaged with numerous implementing partners, health officials and health distributors across East Africa as part of our customer acquisition plan. It is important to remember that the end-users of a medical product and the buyers are usually two different entities. An effective marketing strategy should present a complete value proposition to appeal to both parties.

Conclusion

While many medical device innovators aspire to transition their concepts through regulatory approval and mass production to widespread adoption, very few are able to make it across that finish line. The journey is fraught with setbacks and challenges that unfortunately leave many promising ideas sidelined or abandoned.

Through our own experience developing the neoGuard product, we have learnt that the process takes an exceptional amount of effort, agility, resilience, patience, funding, and overall-teamwork. The myriad of problems that innovators face can be successfully managed or even avoided through interdisciplinary collaboration. To increase the likelihood that a solution will be actualized, innovators should surround themselves with engineering, clinical, manufacturing, regulatory, and marketing expertise at an early stage of their product lifecycle.

Data Availability Statement

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

Ethics Statement

The studies involving human participants were reviewed and approved by Makerere University School of Public Health Higher Degrees Research Ethics Committee and the Tufts Medical Center Institutional Review Board. Written informed consent to participate in this study was provided by the participants' legal guardian/next of kin.

Author Contributions

AN and SS discussed the lessons learned. TC, MT, and RK wrote content for the background on product development, early testing, and clinical validations studies. BA and NK contributed to the introduction and clinical components of the paper. All authors contributed to the final manuscript.

Funding

This project received funding from the Efficiency for Access Research and Development Fund (RD0002) and Grand Challenges Canada (1911-30987).

Conflict of Interest

TC and SS are the innovators of the neoGuard product and co-founders of Neopenda, PBC. AN and MT are employed by Neopenda, PBC. This project received funding from the Efficiency for Access Research and Development Fund. The funder had no involvement in the product development or research efforts discussed here.

The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher's Note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Abbreviations

Bpm, Beats per minute; Brpm, Breaths per minute; COVID-19, Coronavirus disease 2019; DHF, Design History File; EMC, Electromagnetic Compatibility; EU MDR, European Union Medical Device Regulation; HFUE, Human Factors Usability Engineering; IEC, International Electrotechnical Commission; IRB, Institutional Review Board; ISO, International Organization for Standardization; LMICs, Low-and-middle income countries; MakSPH, Makerere University School of Public Health; NBCU, Newborn Care Unit; PMCF, Post-Market Clinical Follow-up; PR, Pulse Rate; RR, Respiratory Rate; RRH, Regional Referral Hospital; SpO 2, Blood oxygen saturation; UCSF, University of California San Francisco; VOC, Voice-of-Customer.

References

9. European Parliament Council of the European Union. Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on Medical Devices, Amending Directive 2001/83/EC, Regulation (EC) No 178/2002 and Regulation (EC) No 1223/2009 and REPEALING COUNCIL Directives 90/385/EEC and 93/42/EEC (Text with EEA relevance). (2017). Available online at: https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=uriserv%3AOJ.L_.2017.117.01.0001.01.ENG (accessed Augest 10, 2021).

10. De Maria C, Di Pietro L, Díaz Lantada A, Madete J, Makobore PN, Mridha M, et al. Safe innovation: on medical device legislation in Europe and Africa. Health Policy Technol. (2018) 7:156-65. doi: 10.1016/j.hlpt.2018.01.012

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Glossary
CE mark
An administrative marking that indicates conformity with health, safety, and environmental protection standards for products sold within the European Economic Area.
Class IIb medical device
A category for medical devices with medium-to-high risk, such as incubators, long-term corrective contact lenses, surgical lasers, vital sign equipment, and defibrillators.
Design Controls
Interrelated practices and procedures that are incorporated into the product design and development process, i.e., a system of checks and balances. Design Controls increase the likelihood that the design transferred to production will translate into a device that is appropriate for its intended use. For medical devices, the rigor of the Design Controls is prescribed by ISO 13485.
Design Freeze
The point in the design and development process at which the product is considered "done" and the baseline design is completed. Under ISO 13485-guided medical device development, changes to the design after the Design Freeze point are subject to engineering change control requirements such as traceability, impact analysis, risk assessment, verification, and validation.
Design History File (DHF)
A compilation of documentation that describes the design history of a finished medical device.
Declaration of Conformity
It is a formal declaration by a manufacturer, or the manufacturer's representative, that the product to which it applies meets all relevant requirements of all product safety directives applicable to that product.
Human Factors Usability Engineering (HFUE)
The application of knowledge about human behavior, abilities, limitations, and other characteristics to the design of medical devices (including software), systems and tasks to achieve adequate usability of the end product.
Technical File
A set of documents that describes a product and can prove that the product was designed according to the requirements of a quality management system.
Voice-of-Customer (VOC)
Customer's feedback about their experiences with and expectations of a product.

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Developing Medical Technologies for Low-Resource Settings: Lessons From a Wireless Wearable Vital Signs Monitor-neoGuard

# data[].attributes.attachment_link.description
The neoGuard™ technology is a wireless wearable vital signs monitor attached to a patient's forehead to continuously measure oxygen saturation, pulse rate, respiratory rate and temperature. Developed with feedback from more than 400 health workers, primarily in East Africa, the product has been designed to meet the unique constraints of low-resource settings.

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While rapid tests have the advantages of being faster at getting results, are generally more affordable, require less training to administer and read, and can be better produced in large quantities, they are generally less reliable. You are trading convenience for reliable results. They are most likely to produce a false positive/negative.

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Thinking of all the stakeholders early on is essential to the success of the product as they will be those who fund, buy, or even use the product.

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Optical point of care devices for diseases such as diabetes, cancer, Eosinophilic esophagitis.

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3D printed prosthetics
Prosthetics are expensive so having a low cost option that can be printed specifically for a person is interesting.

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Pros: rapid, low cost, convenient
Cons: low sensitivity and specificity, misinterpretation of results

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A few pros to using rapid diagnostic tests include the fact that they don often require trained personnel to conduct them, they are low cost, and because of their speed they are better suited for low resource environments because patients might not have a reliable transportation, mailing services, or internet connection. It is beneficial patients get their result right away. A few cons of using rapid diagnostic test include the lack of accuracy due to the cheaper nature of the tests and reliability.

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https://www.frontiersin.org/articles/10.3389/fmed.2021.639208/full
Many children are born with sickle cell anemia and their families have no idea. A new device, Gazelle, uses a microchip based cellulose acetate electrophoreses test. The machine uses a battery to work, and tests can be run all day on a single charge. It can also connect to bluetooth and wifi, so it can connect to a cell phone or print results. It provides point of care results, the most useful in low resource settings. It addresses many problems with diagnosing sick cell anemia in low resource communities, specifically India and Africa, their target market.

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ICMR-National Institute of Research in Tribal Health (NIRTH), Jabalpur, India

Hemex Health, Portland, OR, United States

Sickle cell disease is a major public health problem in India. Lack of rapid and reliable diagnostic methods result in many avoidable deaths in affected population. Current diagnostic tools are laboratory based, expensive and need trained manpower. Here, we evaluated the performance of a microchip-based cellulose acetate electrophoresis test, "Gazelle" in the tribal-dominated Indian states of Chhattisgarh and Madhya Pradesh. A total of 1,050 patients were screened by sickle cell solubility, hemoglobin (cellulose acetate) electrophoresis, high-performance liquid chromatography (HPLC) and Gazelle. Of the total 1,027 test results obtained, 960 tests were "Valid" (93.5%) and included in the analysis. Gazelle identified all patients with disease (HbSS and Thalassemia Major) with 100% accuracy. Gazelle demonstrated 100% sensitivity when comparing sickle cell disease (SCD) vs. sickle cell trait and SCD vs. normal. Specificity was 98.9% and 99.5% when comparing SCD vs. trait and trait vs. normal, respectively. Specificity was 99.8% when comparing SCD vs. normal and sensitivity was 99.3% when comparing trait vs. normal. Overall, Gazelle yielded a high accuracy (99.0%) compared to reference standard tests (hemoglobin electrophoresis and HPLC). Gazelle is a low-cost, rapid diagnostic test with high accuracy for detecting SCD both quantitatively and qualitatively. Gazelle can be a potential screening tool for the rapid diagnosis in resource limited settings and developing countries with high burden of hemoglobin disorders.

Introduction

Hemoglobinopathies are the most common autosomal hereditary disorders. Approximately 7% of the global population carries hemoglobin gene mutation including structural hemoglobin variants like sickle hemoglobin or thalassemia ( 1- 3). Hemoglobin S is highly prevalent in sub-Saharan Africa ( 4), Mediterranean region, India and Southeast Asia ( 5). India alone contributes about 15% of all sickle cell anemia (SCA) newborns worldwide ( 6). An estimated 20% children with sickle disease die in India before the age of 2 years ( 7) and 30% of tribal children with sickle cell disease (SCD) die before the age of 5 years ( 8). Prevalence of SCA is predominantly found among 3 socio-economically disadvantaged ethnic groups; the Scheduled Tribes, the Scheduled Castes and Other Backward Class communities in India ( 9). Jagdalpur, Chhattisgarh is a tribal dominated district in India and is mirrored in the fact that a majority of the patients belong to Scheduled tribe communities (58.7%) followed by Scheduled castes (18.7%) and Other Backward classes (17.9%). Tribal populations constitute 8.6% of the total Indian population and the prevalence of sickle cell carriers and SCD among these different tribal groups varies from 1 to 40% and 1to 2%, respectively ( 10).

Hemoglobin S is a structural variant of normal adult hemoglobin caused by replacement of glutamic acid by valine at position 6 of beta-globin ( 11- 13). This mutation causes polymerization of HbS in low oxygen conditions which can distort red blood cells into a sickle, or crescent, shape. Recurrent sickling episodes lead to RBC lysis. Sickle cell anemia is characterized by pain crisis, severe anemia, jaundice, infarction, stroke, etc. resulting in high morbidity and mortality ( 14).

Heavy morbidity and mortality among rural and tribal populations is mainly due to lack of diagnosis. Early diagnosis is crucial to initiating life-saving therapies and knowledge of sickle cell carrier status is critical to prevention and parental planning for at-risk populations. Currently, only a few public health facilities for diagnosis of SCD and patient care exist. Moreover, with no universal screening program in place, the overall burden of SCA remains unidentified. Although, in 2015, the Govt of India initiated a program for screening SCA among tribal school children, only a few states have implemented this program. In this program, low cost sickle solubility test was used due to the absence of high-performance liquid chromatography (HPLC) and hemoglobin electrophoresis. These gold standard tests require advanced laboratory facilities, trained staff and are slow and have high input costs. Though sickle solubility and sickling slide tests are popular field tests and are considered to have high sensitivity, they cannot differentiate between carrier and disease status ( 15). In addition, the limit of detection of solubility tests depend on Hb percentage, coinheritance of alpha-thalassemia, hereditary persistence of fetal hemoglobin, increased serum viscosity, hyperlipidemia, elevated serum proteins, etc. that may result in false negative or false positive test results. On the other hand, sickle-slide test has fewer limitations, but requires a light microscope, longer incubation time, and trained microscopists. Poor slide preparations result in false negatives. In this context, there is an urgent need for an affordable, portable, easy-to-use, accurate, point-of-care tests for SCA testing in resource-limited countries.

"Gazelle" ( Figure 1) is a portable microchip electrophoresis platform that includes a reader and cellulose acetate cartridge for identifying the most common hemoglobin variants at the point-of-care in low-resource settings ( 16). Here, we report the diagnostic performance results from a field study of Gazelle.

Figure 1. Gazelle-microchip electrophoresis: (A) Gazelle Reader with Cartridge. (B) Steps of Gazelle Hb Variant Procedure.

Materials and Methods

The study was conducted at the sickle cell clinic of ICMR-National Institute of Research in Tribal Health (NIRTH) at Late Baliram Kashyap Medical college, Jagdalpur, Chhattisgarh during August 2018 and November 2019. The study protocol was approved by the Institutional Ethical Committee of ICMR- National Institute of Research in Tribal Health, Jabalpur, India (NIRTH/IEC/1153/2017) and Health Ministry's Screening Committee (HMSC) ICMR, India. Informed consents were obtained from all study participants. The study was supported by Hemex Health, Portland, Oregon, United States of America and one of authors is affiliated to the company.

Gazelle

Details of the Gazelle (HemeChip) design have been previously published ( 16). Briefly, Gazelle is a single-use cartridge-based test that enables rapid, affordable, quantitative, accurate diagnosis for both SCA and carrier status at the point of care. It is a cellulose acetate-based microchip electrophoresis system within a portable instrument, utilizing the principle of standard electrophoresis method with inbuilt analysis software, electronic data storage, and wireless data transmission capabilities. The device is operated by rechargeable lithium batteries that can test all day on a single charge. The device also carries advanced features like WiFi, GPS, and Bluetooth enabled connectivity for easy tracking of samples and can connect to a printer wirelessly.

Study Design and Participants

Clinical study design, study participants, sample size calculation, and details on test methods are described according to the Standards for Reporting Diagnostic Accuracy (STARD) guidelines ( 17).

Based on preliminary studies with HemeChip (pre-Gazelle prototype) ( 16), an evaluation of 1000 samples with Gazelle was planned. Blood samples were collected from patients visiting Late Baliram Kashyap Medical College, Jagdalpur, Chhattisgarh either for treatment of anemia or the antenatal clinic. Inclusion criteria included: subjects of age 6 months to 65 years with or without the signs and symptoms of pallor, jaundice, abdominal pain, joint pain and all pregnant women. A signed informed consent (either by the subject or by the parent as appropriate if the subject is a minor) was required for study inclusion. Subjects with a history of blood transfusion in the previous 3 months and those who withdrew their consent after enrolling were excluded from the study.

No incentives were provided to the subjects or staff for participating in the study. Patients who participated in the study received medical care according to standard procedures of the site. Test results from Gazelle were not made available or used for medical care.

Blood Sample Acquisition and Testing

From each subject, 2 mL of peripheral blood were collected in a vacutainer containing EDTA as an anticoagulant. All samples were tested by sickle solubility test ( 18), standard laboratory-based reference standard cellulose acetate electrophoresis ( 19) and Gazelle. Sickle positive samples were also confirmed by HPLC using betathal short program (VARIANT™ II, Bio-Rad Laboratories, Inc., Hercules, California, USA). HPLC and standard cellulose acetate electrophoresis were considered to be the reference standard for our comparisons.

Clinical information and reference test results were not available to the performers of the test or the study team at the time of testing. Similarly, Gazelle test results were not available to the performers of the standard reference tests. Sickle solubility test, cellulose acetate hemoglobin electrophoresis, complete blood count and Gazelle testing were carried out at the sickle cell clinic of ICMR-National Institute of Research in Tribal Health, Jagdalpur, Chhattisgarh. Per protocol, HPLC testing was planned for at least one-third samples testing positive for SCD or SCD Trait. HPLC was performed at ICMR-NIRTH Laboratory at Jabalpur.

Samples for Gazelle were processed as per manufacturer's instructions ( Figure 1). Briefly, 20 μL blood was mixed with 40 μL lysing solution. The cellulose acetate membrane inside the Gazelle cartridge was pre-wetted with TBE buffer (50 μl at pH of 8.4) and lysed blood sample stamped with a stamper. Next, 200 μl TBE buffer was added to both buffer wells and the cartridge was placed in the Reader and charge was applied. Migration and separation of various bands was completed in 8 min. At this end point, the bands were automatically identified by the inbuilt custom software in the reader. Results on Gazelle are easy to read as the identity and quantity of different Hb variants are displayed on the reader ( Figures 2A,B).

Figure 2. Gazelle shows qualitative and quantitative measurements of various hemoglobin variants. (A) Microchip electrophoretic image showing separation of HbA and HbS with per cent quantification. (B) Diagrammatic representation of various hemoglobin variants.

Statistical Methods

Diagnostic accuracy of Gazelle in comparison to hemoglobin electrophoresis was determined as the percent ratio of correct tests results, and summation of correct tests results and incorrect test results for a hemoglobin variant category. Sensitivity was determined as the ratio of true positive results divided by the summation of true positive results and false negative results. Specificity was determined as the ratio of true negative results divided by the summation of true negative results and false positive results.

Results

Participants

Overall, 1,050 subjects participated in this study. The average age of participants was 22.4 years. The majority of the participants were from Scheduled Tribe communities (617/1050; 58.7%), followed by Scheduled Caste (197/1,050; 18.76%), Other Backward caste (OBC; 188/1,050; 17.9%) and General caste (48/1,050; 4.6%). Of these, 259 (24.7%) participants were male and rest were female. A total of 1,050 samples were collected and screened for SCA by sickle solubility, hemoglobin (cellulose acetate) electrophoresis and Gazelle. HPLC analysis was also performed on a subset of 186 samples.

Gazelle Performance

A total of 960 samples were included in the analysis; 23 samples were not included in the analysis: data files were not received due to communication error for 16 samples and seven samples due to probable sample mix ups.

Of the total 1,027 test results obtained, 960 tests were "Valid" (93.5%) and included in the analysis, 41 tests were "Uninterpretable" (4.0%), and 26 tests were "Inconclusive" (2.5%) ( Table 1). An "Inconclusive" or "Uninterpretable" test does not result in a diagnostic decision. As such, when an "Inconclusive" or "Uninterpretable" test is encountered, the test can be repeated or other methods of testing can be utilized, which are common practices in diagnostics, as well as in hemoglobin testing. Therefore, based on recommended practices in the literature and the STARD guidelines, the inconclusive and uninterpretable test results were reported separately in this study ( Table 1).

Table 1. Overview of diagnostic tests with Gazelle.

In the analysis, 65 samples were positive for sickle cell anemia by electrophoresis, solubility, and device, 347 samples were positive for Sickle cell trait by all 3 methods ( Figure 3) and 604 samples were normal (HbAA) by all methods ( Table 2). Gazelle test results from this study included SCD-SS (Hb SS), SCD Trait (Hb AS), Hb E Trait (Hb AE), Beta Thalassemia Major and Normal (no abnormal Hb, or Hb AA). Gazelle identified subjects with disease, SCD-SS with 100% accuracy ( Table 2). Two Beta Thalassemia Major subjects were identified as Hb SS disease by Gazelle. Two samples with traits (Hb AS) were identified as normal (Hb AA) due to light S bands, 2 were identified as SS and one was identified as SF by Gazelle. Three subjects with no abnormal Hb (Hb AA) were identified as AS due to smearing of the bands and one was identified as SS by Gazelle ( Table 2). Gazelle yielded an overall high accuracy (99.0%) compared to reference standard tests (HPLC and hemoglobin electrophoresis).

Figure 3. Venn diagram depicting the comparative performance of different sickle diagnostic tests. The overlap result of diagnostic test showed that 347 samples with HbS were found to be positive in all 3 different tests.

Table 2. Diagnostic accuracy of Gazelle compared to hemoglobin electrophoresis.

Sensitivity and negative predictive value (NPV) were 100% for SCD-SS vs. other hemoglobin variants ( Table 3). Specificity was 99.3% for SCD-SS vs. others, and 99.6% for SCD Trait vs. others ( Table 3). Positive predictive value was 91.8% for SCD-SS vs. others, and 98.9% for all SCD Trait vs. other types ( Table 3). Gazelle showed 100% sensitivity when comparing disease vs. trait and disease vs. normal. Specificity was 98.9% and 99.5% when comparing disease vs. trait and trait vs. normal, respectively. Specificity was 99.8% when comparing disease vs. normal and sensitivity was 99.3% when comparing trait vs. normal.

Table 3. Gazelle diagnostic sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) in comparison to reference standard method.

For clinical studies that report diagnostic accuracy, published guidelines recommend excluding inconclusive results from sensitivity and specificity analyses, instead, an additional summary statistic can be reported that accounts for inconclusive results ( 16). Gazelle yielded a diagnostic accuracy of 93.5% in the additional analysis wherein inconclusive tests were considered as incorrect. Quantification for 161 multi-band tests with the same phenotype between Gazelle and HPLC demonstrated a Pearson correlation coefficient of 93.3% ( Figure 4). No adverse events were reported during the study. False-negative sickle-solubility test reactions are known to occur with insufficient quantities of blood from anemic patients (hemoglobin levels <8.0 g/dL). Four hundred and fifty-one samples had Hb levels lower than 8.0 g/dL and in such cases minimum 2 volumes (40 μL) were used for solubility test. In contrast, Gazelle could detect presence of HbS even in samples where Hb levels were lower than 4.0 g/dL without increasing input volume (data not shown). In all, 152 samples had Hb levels lower than 4.0 g/dL.

Figure 4. Comparison of hemoglobin quantification percentages between normalized HPLC and Gazelle. *Note: This is applicable to all Hb types, not only HbS. Graphic representation of Pearson Correlation Coffeficient analysis.

Discussion

In this point-of-care field study conducted in a remote tribal area, Gazelle exhibited high sensitivity and specificity for detection of Hb types, HbA, HbS, and HbF, and high sensitivity and specificity for each relevant Hb phenotype (normal, carrier, and disease states). Notably, all subjects with SCD were identified with Gazelle.

Despite their inability to differentiate between carrier and disease status, solubility and sickling slide tests are popular field tests that are often employed for sickle cell diagnosis ( 15). Follow-on confirmatory tests such as HPLC or hemoglobin electrophoresis are needed and these tests require advanced laboratories ( 20). Furthermore, advanced laboratory techniques require trained personnel which are lacking or in short supply in underdeveloped and developing countries, a situation which is more acute in areas of high prevalence of hemoglobin disorder. Gazelle is a low cost, rugged device designed for low resource settings. It has a built-in software that detects errors occurring during sample preparation or testing process and calls automatic retests. It has an automated analysis system to perform interpretation of each sample. This feature has been shown to limit user errors in pilot studies and is also supported by Gazelle's extremely low frequency of discordant results in this study. The short test time allows testing while the patient waits to ensure that test results reach the patient and clinical intervention, if needed, can start immediately. One other Gazelle feature that limit user errors and the time needed for training is the included step by step instructions displayed on the screen to guide the user during the testing process. Also, customized reports can be generated from the device and with the traceability of reports and data, clinicians or laboratories can maintain a record of patient's history. Test results can be stored on the reader, saved in the Cloud or printed.

In this study, Gazelle, a new point-of-care, microchip-electrophoresis based sickle diagnostic device was compared to conventional laboratory-based hemoglobin electrophoresis and HPLC. The sensitivity and specificity of the Gazelle is comparable to hemoglobin electrophoresis and HPLC and eliminates the need for a laboratory. Gazelle yielded an overall high accuracy (99.0%) compared to reference standard tests (HPLC and hemoglobin electrophoresis). These results were consistent with the accuracy of a previously described prototype version of Gazelle, HemeChip ( 16). The overall diagnostic accuracy of HemeChip was 98.4% in identifying SCD-SS, SCD-SC, SCD Trait, Hb E Disease, Hb E Trait, and Normal ( 16). Although, Gazelle showed an accuracy of 93.5% in additional analysis wherein inconclusive test results were considered are incorrect, these results represent a hypothetical condition. In the real-world setting, an inconclusive test results would not yield a wrong diagnosis as Gazelle prompts a retest. Two Beta thalassemia major subjects were incorrectly identified as Hb SS disease by Gazelle which is a limitation of the present algorithm, but its capacity to identify Beta thalassemia as "disease" is useful. Furthermore, it would be beneficial to test more samples with high HbF and relatively lower HbA or HbS for improving the current diagnostic algorithm for accurate detection of beta thalassemia and other variants. It may be noted that the current study recruited subjects only between the ages of 6 months to 85 years as per inclusion criteria. In all only 2 infants of age 1 year were recruited. No newborn or infant <6 months were included in the study as current version was not suitable for newborn screening. The improved version of "Gazelle" with multispectral imaging and newer algorithm and software has been found suitable for newborn screening (Personal Communication).

Gazelle offers the benefit of both standard hemoglobin electrophoresis and a point-of-care test. Gazelle replaces the bench top laboratory setup with a portable reader and replaces the hemoglobin controls with a blue control marker ( 19, 20). On an average it took about 13 min from drawing of blood sample to completing the run on Gazelle. The entire process was about 8 times faster than hemoglobin electrophoresis (~2-3 h) and comparable to HPLC (~10 min), however, as HPLC is run as a batch, the time from sample draw to result was much longer. Gazelle provides hemoglobin type identification and quantification simultaneously and offers a complete interpretation of test results, thus avoiding transcription and interpretation errors. The current study showed that identification of various hemoglobin variants by Gazelle was equivalent to those obtained in hemoglobin electrophoresis or HPLC. Furthermore, hemoglobin electrophoresis is labor intensive, time consuming and laboratory dependent compared to HPLC which is also cost intensive and requires a laboratory setting.

To counter high cost burden of advanced laboratories, a need for a low-cost reliable point of-care test with high accuracy and specificity is needed. In addition to clinical benefits, economic benefit has been one of the primary objectives of Gazelle design ( 16).

These are several features of Gazelle that makes it a potential diagnostic tool for field use in detection and management of SCA endemic areas of the world. Gazelle is a rugged, battery-operated cartridge-based point-of-care, sickle diagnostic device that is easy to use and quickly provides accurate results in the field. The quick turnaround times and low-cost test can enable clinicians to perform widespread screening affordably and quickly identify carriers of sickle hemoglobin. Gazelle provides easily readable qualitative as well as quantitative results that are electronically stored and can be transmitted. One other Gazelle feature that limits user errors and the time needed for training is the included step by step instructions displayed on the screen to guide the user during the testing process. Overall, this study adds to the increasing evidence that microfluidic electrophoresis assays may be a valuable tool for early identification of affected population resulting in better clinical management and reduction in morbidity and mortality due to SCD. Gazelle has a high sensitivity and specificity in detection of SCD and SCD trait. Diagnostic accuracy of Gazelle is comparable to conventional hemoglobin electrophoresis testing. Gazelle's low cost, need for minimal training, portability, and fast test turnaround time makes it ideally suited for low-resource settings, wherein Gazelle can facilitate quick diagnosis and early clinical management of hemoglobin disorders. Future work on extending the test to newborns and identifying additional hemoglobin variants would be beneficial.

Data Availability Statement

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding authors.

Ethics Statement

The studies involving human participants were reviewed and approved by Institutional Ethical Committee of ICMR-National Institute of Reaserch in Tribal Health, Jabalpur, M.P., India. Written informed consent to participate in this study was provided by the participants' legal guardian/next of kin.

Author Contributions

AD, PT, RS, and PB designed the study and critically reviewed the manuscript. MP, RK, AV, SS, RU, and ST collected the samples and executed the experiments. PT, RS, PB, and AD provided resources and infrastructure for the study. AV, AG, RK, SS, and PB analyzed the data. SS, AV, PT, PB, and RS wrote the manuscript. All authors read and approved the manuscript.

Funding

RS reports grants and non-financial support from Hemex Health, USA. Grant Number: GZL-M10-001.

Conflict of Interest

RS reports grants and non-financial support from Hemex Health, USA. PT is an employee of Hemex Health USA.

The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The reviewer SSM declared a shared affiliation with several of the authors SS, MP, RK, AG, RU, ST, AV, AD, PB, and RS to the handling editor at time of review.

Publisher's Note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Acknowledgments

We are thankful to all study participants, DMO, BMO, CMHO and supporting staff for their kind support and cooperation at study site during the course of the study. The manuscript has been approved by the Publication Screening Committee of ICMR-NIRTH Jabalpur and assigned with the number ICMR-NIRTH/PSC/48/2020.

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# data[].attributes.attachment_link.title
Evaluation of Microchip-Based Point-Of-Care Device "Gazelle" for Diagnosis of Sickle Cell Disease in India

# data[].attributes.attachment_link.description
Sickle cell disease is a major public health problem in India. Lack of rapid and reliable diagnostic methods result in many avoidable deaths in affected population. Current diagnostic tools are laboratory based, expensive and need trained manpower. Here, we evaluated the performance of a microchip-based cellulose acetate electrophoresis test, "Gazelle" in the tribal-dominated Indian states of Chhattisgarh and Madhya Pradesh.

# data[].attributes.body
It is important to think of all stakeholders throughout the design process because each of a stakeholder's needs will have an impact on the success of a product. For example, investors will be funding a product so their needs must be met to continue funding and keep them satisfied. Most importantly, consumers and patients will be using the product, so if their needs aren't met, the product is deemed unsuccessful.

# data[].attributes.body
Dr. Locke's research focuses on optical biosensing for POC monitoring and diagnostics, while emphasizes its efficacy in low resource settings in the treatment of conditions such as oral cancer, diabetes, and cardiac disease.

# data[].attributes.body
The device that I found is the "Do-It-Yourself" pH-stat device, which can be used for measuring PH, using a simple Arduino-based circuit and open source software to measure pH values and maintenance. This device is interesting to me because of its versatility, as it can be applied to a variety of situations, from maintaining and monitoring pH levels in a lab to simply measuring the pH levels of one's drinking water.
Source: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0193744

# data[].attributes.body
Pros of using rapid diagnostic tests include that there is a relatively low cost, quick results, and multiple things can be tested at once. Cons include that there is a lower sensitivity and specificity, which can lead to a higher chance of misdiagnosis.

# data[].attributes.body
It is important to think about all of the stakeholders throughout the design process.  Stakeholders include patients, clinicians, and even family members.  Without their whole hearted support, a device will not be used and will not help anyone.

# data[].attributes.body
Dr. Locke focuses on optical biosensing for point of care diagnostics and monitoring. She is looking closely at diabetes, cardiac diseases, and GI problems.

# data[].attributes.body
Stakeholders are important when designing a product since they cover various parts of the design process such as R&D, and regulatory approval and rsearchers needs to cover all these areas properly.

# data[].attributes.body
Dr. Locke's focus is on optical biosensing for POC monitoring and diagnostics.

# data[].attributes.body
Scientists in India have developed a portable and low cost screening tool for diagnosing oral cancer. What's impressive is that it is only $500 while a typical OCT device might cost up to $35,000. The central innovation in this work can detect cancer of superficial locations in the body with very little margin of misclassification.

https://www.thebetterindia.com/275217/iit-kharagpur-innovation-oral-cancer-screening-cheap-device/

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IIT-KGP Scientists Develop Low-Cost Device That Screens Oral Cancer in 10 Mins

# data[].attributes.attachment_link.description
Scientists at the Indian Institute of Technology Kharagpur (IIT-KGP) have developed what they are calling a “highly accurate, portable, yet user-friendly,

# data[].attributes.body
Some pros are the quick turnaround times and low cost. Some cons are low sensitivity and the training that is required.

# data[].attributes.body
Rapid tests are usually lower cost and give quicker results to the patient. However, they can be lest accurate and require more training to use and interpret.

# data[].attributes.body
It is very important to think about all of the stakeholders throughout the design process since they are the ones who have a direct influence on the product. In other words, since they are typically funding or using the product, their insight is critical to the development and overall success of the product. They often bring in different perspectives and provide significant feedback to help make the product the best it can be.

# data[].attributes.body
Dr. Locke's research focus is point-of-care technology. More specifically, Dr. Locke is focused on optical sensing platforms for monitoring diabetes, oral cancer, gut function, and more.

# data[].attributes.body
The Wright Research Group at Vanderbilt developed an antibody-free, malarial assay based on the phenomenon that forms coffee ring stains on a kitchen counter. The microfluidics present in an evaporating drop of colloidal solution create a "coffee ring" stain of small particles that are visible with the naked eye. With a droplet containing the histidine-rich protein-II (HRP-II) of P. falciparum, a visible

colorimetric ring is produced indicating malaria. What I find most interesting about the coffee ring diagnostics is the ability to explore beyond the formation of the coffee ring itself. Researchers involved are exploring how the surface chemistry of the glass slide impacts the formation of the ring to ultimately address many of the current issues with low-resource malarial diagnostics.

# data[].attributes.body
It's important to consider the interests of all possible stakeholders when designing a device because different groups of people tend to have different priorities, wants, needs, and concerns. In order to have a functional, useful, and marketable product, you absolutely should do some degree of research into the groups of people involved in the design and sales processes to ensure you can successfully market your product and get it to people in need.

# data[].attributes.body
Dr. Locke currently researches optical techniques for point-of-care monitoring and diagnostics for diabetes, oral cancer, gut function, premature birth, and cardiac disease.

# data[].attributes.body
It is important to think about share holders because this will give you better insight on the creation of the device. They are the ones who will be funding, using, or buying the device, so it is better to gain their perspective to optimize the device.

Mohamed Adan

# data[].attributes.body
Dr.Lockes research focusing on optical bio sensing for point and care diagnostics

Mohamed Adan

# data[].attributes.body
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0179133

This device is a low cost PCR machine. The pieces are 3D printed and made to be as cheap as possible. What I find interesting about this is it is not only limited to one disease. It can be used for many infectious diseases like HIV and malaria. Even though these communicable diseases prevalence is decreasing, doesn’t mean we should stop putting effort into them.

Mohamed Adan

# data[].attributes.body
Some pros to rapid diagnostic tests are the cheap cost, quick diagnosis, and easily accessible. Some cons are the lack of sensitivity and specificity.

Mohamed Adan

# data[].attributes.body
It is important to consider all of the stake holders throughout the design process - the patient, clinician, investors,  and safety regulators - due to the fact that all of these people are involved with the product and their perspectives come together to determine the overall success of the product being created. The patient is using the product, the clinician implements it, investors provide the money for it and safety regulators ensure the product is safe before it can be brought to market. These stakeholders also provide insight to changes the product may need and things to implement in order for the product to do everything it needs to.

# data[].attributes.body
Some major pros to using diagnostic tests are the relatively low costs, quicker receival of results, and their ease of use in low-resource areas. Although these benefits are substantial, the rapid diagnostic tests are typically less accurate and can lead to misinterpreted results.

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https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0019738

Nucleic acid diagnostic tests are instrumental in modern medical diagnostics, but are widely inaccessible in low resource settings due to power requirements and complex instrumentation required to run PCRs. A new method of detecting nucleic acid markers is being developed in which isothermal nucleic acid amplification assays are able to be incubated with an electricity-free heater. This heater operates via exothermic chemical reactions and phase change materials. This method's assays has been found to be comparable to PCR instrumentation that is currently available. These findings indicate the possibility for nucleic acid testing without power requirements, thus allowing for widespread use in low resource settings.

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A Simple, Inexpensive Device for Nucleic Acid Amplification without Electricity-Toward Instrument-Free Molecular Diagnostics in Low-Resource Settings

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Background Molecular assays targeted to nucleic acid (NA) markers are becoming increasingly important to medical diagnostics. However, these are typically confined to wealthy, developed countries; or, to the national reference laboratories of developing-world countries. There are many infectious diseases that are endemic in low-resource settings (LRS) where the lack of simple, instrument-free, NA diagnostic tests is a critical barrier to timely treatment.

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It's always important to communicate with stakeholders (patients, clinicians, safety regulators, investors, etc.) throughout the design process since, without them, there will be no way to create, distribute, and use the product. The stakeholders are the primary parties responsible for funding and implementing the product. Keeping those groups of people satisfied and informed throughout the design process is essential for the product to be used and have the idea reach its maximum potential.

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Dr. Locke's research focus is optical biosensing for point of care monitoring and diagnostics. Her goal with this technology is to eventually apply it for diagnosing and monitoring diabetes, cancer, cardiac diseases, and pre-term birth.

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This is a new CRISPR-based malaria test that uses the 'SHERLOCK' protocol, seeking to give the accuracy of PCR-based tests using a small form factor with the speed of RDTs. It delivers results in 60 minutes and can differentiate between multiple strains of P. falciparum and P. ovale malaria with specificity. It is especially useful in low resource settings since it can detect prevalence in asymptomatic patients.

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Malaria Minute Podcast: CRISPR-Based Malaria Test Useful for Low-Resource Settings | Mesa

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Click on the image above to listen to the podcast by Fight Malaria: A new malaria test offers high specificity from a small form factor, and researchers develop an imaging tool to examine mosquito feeding behaviour Script

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Rapid diagnostic tests are beneficial in low resource settings due to their capability of quick results, low cost per test, and accessibility. However, these tests often must compromise some accuracy and may require skilled professionals for operation and/or interpretation of results.

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Dr. Locke's research focus is the use of optical biosensing technologies for point of care diagnostics in low resource settings.

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It is important to consider all stakeholders throughout the design process because they are the ones who will fund and use the device in order to keep it successful on the market. For instance, if investors support the device but physicians do not, there will be no market for the device and it will be an unsuccessful product. By considering all perspectives throughout the design process, engineers can ensure that their device is able to have a widespread impact on patients.

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DRW (Diagnostics for the Real World) developed the SAMBA II, a point-of-care diagnostic device for the detection of infectious diseases, including HIV and HCV, for use in low-resource and/or remote regions. The system employs nucleic acid amplification to detect viral RNA or DNA in whole blood or plasma samples. The feature that I found to be most interesting with this device was that the assay connects to a tablet via bluetooth for the storing of results and this can be emailed for sharing of results when there is internet available, or texted if there is service but no internet.

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Dr. Locke's research is focused on optical biosensing for point-of care monitoring and diagnostics. Her research has applications for diabetes, cardiac disease, GI conditions, and premature birth.

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Pros of rapid diagnostic tests are the lower costs, quick turnaround time for results, the ability to test for multiple things at once, and accessibility. Cons include reduced specificity and sensitivity, and ambiguous results that are more likely to be inaccurate than other diagnostic tools.

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It is important to think of the stakeholders at each point in the research and development process because their input consistently determines the need, cost, and usability of the device. If at any point they believe it is not a worthy investment, or doesn’t effectively solve the problem at hand, there is little motivation behind continuing the project, and reassessment of the situation is needed. In order to be successful and profitable, all stakeholders need to be satisfied with the product and process.

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Dr. Locke’s research focus is using optical biosensing technologies for diagnosis and treatment of disease specifically in low resource areas at the point of care. In particular, she works on diabetes maintenance, oral care, and prenatal issues.

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The lab-on-a-chip or LoC platform is gaining popularity as a point of care diagnostic test for chronic kidney disease. Specifically, non-invasive urinary tests are required to assess renal function throughout the progression of the disease. Coskun et al. developed a low resource LoC fluorescence based urinary albumin test requiring a low volume of sample and a smartphone camera to detect renal function.  This platform provides rapid results needed for long term monitoring and management of chronic kidney disease.  https://www.nature.com/articles/s41746-017-0014-0

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Some of the pros of using rapid diagnostic tests include decreased wait time for the results, a lower cost than alternatives, less training required due to their ease of use, and being able to test for multiple things with one test. Some of the cons, however, include lower sensitivity and specificity and higher misdiagnosis rates.

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It is important to think of all the stakeholders throughout the design process so that you can ensure that the device is successful. Throughout the process, you should continuously gather feedback to address any challenges or concerns to make certain that all stakeholders involved in financially supporting or potentially using your device are happy with the end product.

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Dr. Locke’s research uses optical techniques for point-of-care monitoring and diagnostics for diseases such as diabetes, oral cancer, gut function, pre-term birth, and cardiac disease. During her lecture, Dr. Locke described her prior research in using fluorescence sensing to monitor glucose levels in patients with diabetes to find a solution to the current devices on the market.

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A team of biomedical engineers at the University of Connecticut have developed a simple, inexpensive, and quick technique for diagnosing and monitoring sickle cell disease. The device uses magnetic creates a magnetic field that separates a blood sample based on density (sickle cells are more dense than healthy red blood cells) and captures and displays an image using a smartphone. The entire process takes less than 15 minutes, gives a clear diagnosis if a patient has sickle cell disease, and is simple enough that it would require little training.

https://www.sciencedaily.com/releases/2015/11/151105091757.htm

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Pros:

Quick, easy to use, low cost, can be used in areas with limited access to electricity and refrigeration, can be built for a variety of platforms, many test bodily fluids that can be collected non-invasively

Cons:

Results are less qualitative, tests are less sensitive, some tests require training, can produce ambiguous results if the sample is weak, some tests have steps that can limit usability in low resource settings

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https://www.med-dept.com/medical-kits-contents/u-s-army-x-ray-field-unit/

During WW2, the Waite and Bartlett Company and Picker X-Ray Corporation designed the first mobile and modular x-ray units for use in the field. The devices conception and development had a profound influence on modern x-ray machines.

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Introduction:

Roentgen rays had already been discovered long before the outbreak of WW2. Wilhelm Conrad Röntgen, a German physicist whose discovery would eventually earn him a Nobel Prize, first produced and detected the rays in 1895 whilst working at the University of Würzburg. At first, the findings were called x-rays; but scientists later referred to them as roentgen rays. Soon after their discovery, it was realised that these rays possessed the amazing power of penetrating solids and otherwise opaque media. This power of x-rays distinguishes them from practically all other types of radiation. Professor Röntgen passed the rays through wood, cloth and living tissues during his experiments in November 1895. Later, lead, iron and other heavy materials were shown to be transparent to them in varying degrees. Röntgen demonstrated their property of darkening photographic plates, and that they caused many substances to emit light (i.e. fluorescence). Photographic and fluorescent actions, together with their great penetrating power formed the basis for early applications of the roentgen-ray techniques.

During the interbellum period, the US Army investigated ways to utilize the new technologies that roentgen rays had presented. The Picker X-Ray Corporation had already been investigating potential applications of the roentgen rays in the medical profession, and the company was approached by the US Army in the late 1930s to produce a special x-ray machine that could be used in the field or in fixed hospitals with very little adjustment.

The Picker X-Ray Corporation of New York was one of the pioneers in the development and manufacture of X-Ray equipment for the U.S. Army. It was awarded the Army-Navy "E" (E for excellence) Flag on 28 August 1942, and received its first star 10 July 1943 and a second star 26 February 1944.

Dr. Henry E. Waite founded the original "Waite and Bartlett Company", which manufactured medical batteries, static machines, and electrical equipment serving the medical profession. The electro-medical experience of the company would prove extremely valuable in the development of apparatus to put the newly-discovered x-ray apparatus to practical use.
The Waite Company equipped America's first Hospital Ship, the USS Solace in 1914 with x-ray equipment, and in 1916 the Company working closely together with members of the US Army Medical Division developed and manufactured the original US Army Mobile Bedside X-Ray Unit (first practical use of the hot cathode type x-ray tube).

In 1930, the Picker X-Ray Corporation acquired the assets of the Waite and Bartlett Company, and the new group's achievements greatly influenced the further development of modern x-ray apparatus. Picker-Waite engineers invented, developed, and produced the first completely shock-proof x-ray apparatus as well as the first shock-proof vertical fluoroscope. After an expansion program which took place in 1937, the Company initiated development of a new x-ray unit suited to modern military issues. As it became evident that gasoline-electric generators for proper operation of field equipment were not available, the Picker engineering staff conceived and developed such items for large-scale production during war. Early in the stages of development, transportation became a chief concern, and as result of further study, a strong, compact, and versatile x-ray unit was developed for all emergency situations, yet light enough for convenient transportation by air.
In World War Two, more than 85% of the Picker Corporation production was devoted to field x-ray equipment for the United States Armed Forces, and beside field units, many larger base hospital units were installed in both Army and Navy Hospitals throughout the Zone of Interior.

Picker X-Ray Corporation was the sole manufacturer of x-ray units for the United States Army during WW2. Smaller, less complex items were also produced by other medical laboratory and manufacturing companies, including D. W. Onan & Sons, Inc. (Minnesota) and Westinghouse Electric Company (Pennsylvania). This Article looks at the numerous pieces of field x-ray equipment that were produced exclusively for the US Army during WW2. Each item is presented with its nomenclature, Medical Department Item Number, illustrations and a brief description of the piece.

X-Ray Equipment:
Chest, Film, X-Ray (Item # 96025):
This is simply a standard Medical Department Field Chest containing an inner lining of sheet lead. The sheet lead is of such thickness (approximately 1 1/2mm) that, with the opacity of the Chest itself, there is provided protection against x-rays produced by all Army equipment. This special Chest was designed for use particularly at the Evacuation Hospital and for occasional times when films would be needed for use in a truck at the Mobile Surgical Hospital. This particular Chest is not generally used for the shipment of cassettes, cardboard holders or film, since the additional weight of lead lining is unnecessary. As a result, standard Medical Department Field Chests can be used for this purpose.
Dryer and Loading Bin Combination (Item # 96055):
This unit is intended for General Hospitals, Station Hospitals and Evacuation Hospitals. Occasionally it may be needed for use in a truck. It is portable, being composed of two compartments. The upper compartment is completely lead-lined to afford protection against x-radiation. It consists of two sections: a film storage section occupying the right half, and a loaded cassette section occupying the left half. Racks have been provided in each of these two sections to accommodate the three standard dimensions of x-ray films as used by the Medical Department: 8" x 10", 10" x 12" and 14" x 17".

The lower compartment of the unit contains a drawer type of drying rack, a heater, fan and a floor loading shelf. The drying rack has accommodations for 18 films as suspended on standard film hangers. After mounting the upper compartment (the film and cassette loading bins) onto the lower compartment, there is provided a loading bench. The fixation of these two compartments is accomplished by means of a spring-type lock that is found on the inside of the base compartment and beneath its top.
X-Ray Field Unit, Generator (Item # 96060):
This generator is a specially-designed gasoline electrical generator. It is intended particularly for use where community electrical supply is not available and for emergency needs at other hospital installations. Its functioning capacity is such as to permit the delivery of 2,500 watts of energy. The Generator is designed in such a manner that it can be stored inside a modified Medical Department Field Chest.

Grid, Portable (Item # 96070):
This item is a wafer type of grid included with the later models of the Field Table Unit (Item # 96145) and the Fluoroscopic Foreign Body Localization outfit (Item # 96215), or it may be requisitioned separately for general use. The lead strips of this grid are unusually thin. There are 55 strips per inch width of the grid itself - thus even though it is a stationary type, grid marks are inconspicuous. In the case of the first several hundred that were purchased by the Medical Department, the spacing of the lead strips was such as to provide a true centering (grid radius) at 36 inches; later versions were provided for true centering at 30 inches.
X-Ray Machine Unit (Item # 96085):
This item is intended for all types of hospital installations. It is packed in three Field Chests. Two of these Chests are modified Medical Department Field Chests, the other is of special construction for accommodation of the high tension and filament transformers. The x-ray tube in its housing is packed by setting it in a nest supported by eight springs which are attached to the inside corners of a compartment contained in one of the Field Chests. In addition, this particular Chest accommodates a drum for packing the two shockproof cables, as well as smaller items such as the filters (to be used in roentgenotherapy) and the several aperture diaphragms. This Chest has a gable type of superstructure which has been added in order to emphasize that the chest should be placed on end during transit. This is important in order to provide the greatest protection to the x-ray tube.

The second standard Medical Department Field Chest is modified for accommodation of the Control Unit, the interconnecting cables, the timer and the foot switch. A lead apron, a pair of lead-impregnated gloves and a pair of goggles can also be accommodated in this Chest.

In conjunction with the X-Ray Table Unit (Item# 96145) or the Mobile X-Ray Chassis (Item # 96090), this machine unit is adaptable nine ways: horizontal roentgenoscopy, foreign body localization by means of a rapid roentgenoscopic method, sitting roentgenoscopy, standing roentgenoscopy (to the extent of accommodating routing chest studies and also gastrointestinal studies), horizontal roentgenography (using focal film distances up to 45 inches), 6-foot vertical chest studies, 6-foot horizontal chest studies, ordinary bedside work on wards and superficial roentgenotherapy.

The item is broken down into a number of separate components, each with a specially designated Medical Chest (MD X-#) as follows:
Item # 96086 -X-Ray Field Unit Transformer Unit, Chest - MD X-2
Item # 96087 -X-Ray Field Unit Tube Unit, Chest - MD X-1
Item # 96088 - X-Ray Field Unit Control Unit, Chest - MD X-4
Additional replacement items are available for the unit: X-Ray Field Unit, Shockproof Cable (Item # 96205), X-Ray Field Unit, Tube, X-Ray (Item # 96209), and X-Ray Field Unit, Kit Spare Parts and Repair, X-Ray Machine (Item # 96245). It should be noted that from March 1944 onwards, the Control Unit was produced in two variants, one for the standard 110 volt power supply, and another, which was capable of handling 110-220 volts. These were designated Item # 9608808 and Item # 9608810 respectively.
Mobile Chassis Unit (Item # 96090):
This special chassis has been designed to convert the X-Ray Machine Unit into a mobile unit for use in the wards and at the bedside. It should be of service in the hospitalization section of the Mobile Surgical Hospital, in the Evacuation Hospital, the General Hospital and the Station Hospital. An additional model is provided with wheels of greater diameter and with means of pulling the X-Ray Machine Unit when mounted on it, as well as pushing it. These additional features have been incorporated to facilitate maneuvering the equipment over rough terrain (such as is typically found in the field). This second model is designated Item # 96090-10.

Processing Unit (Item # 96115):
This item has been developed for use in any type of hospital installation. It is designed as two sections; a Master Chemical Section (Item # 96115) and an Auxiliary Wash Tank (Item # 96117)When using the master chemical section alone, 30 to 50 large films can be accommodated within an 8-hour period. With the addition of the Auxiliary Wash Tank, this can be increased to 200 or more films.

The Master Chemical Section consists of a tank compartment and a pedestal or base compartment. The tank compartment has a volume capacity of approximately 50 gallons. The pedestal or base compartment contains a water-circulator unit, a refrigerator unit, a heating unit, a mixing chamber and a thermostatic regulator. The unit is assembled by simply setting the tank compartment upon the pedestal compartment and connecting three water couplings which can be accomplished without the need of tools. The electrical supply required is 115 volts, 50-90 cycle, single-phase. This can be provided by the Gasoline Electrical Generator unit (Item # 99600).

The Auxiliary Wash Tank consists of two compartments; a tank compartment which is identical in dimensions with those of the Master Chemical Tank, and a pedestal compartment. The tank compartment contains two baffles to provide for a cascade type of washing. A pre-cooling system is packed in the pedestal compartment. When in use, the pre-cooling coils are suspended in the tank of the Master Chemical Section.

Both sections of the Processing Unit are composed of two compartments. This provision is for the sake of portability, making the unit practical both for permanent installations and for use in the field. In case of necessity it can be carried in parts to a location where activities may require it. The heating and cooling units as well as the pre-cooler are self-contained and all connections can be made by hand, without the use of any special tools.
X-Ray Table Unit (Item # 96145):
This item is a portable roentgenoscopic and roentgenographic table unit. It is considered practical for usage in any type of hospital installation. Essentially, this unit is composed of two fabricated steel end-pieces, three rails (each composed of three sections), a horizontal carriage and a C-shaped supporting arm for accommodation of the x-ray tube unit and also of the fluoroscopic screen.

The C-shaped arm may be adjusted in several ways:

The x-ray tube and fluoroscopic screen may be positioned so as to provide for horizontal roentgenoscopy, with an allowance of vertical shifting through a range of 16 inches.

They may be positioned so as to provide for vertical roentgenoscopy, the patient being in the sitting position.

They may be positioned to one end of the table chassis so as to provide for standing roentgenoscopy.

The tube housing itself may be rotated to a position so as to provide for chest studies with focal film distances as great as or greater than 6 feet.

In the position for conventional horizontal roentgenography, the tube housing may be raised or lowered so as to provide focal film distances varying from 29 inches to as much as 45 inches, the patient lying on a litter at the table-top level.

The x-ray tube may be rotated in the horizontal plane so as to provide for chest studies of focal film distances as great as 6 feet, the patient lying upon a litter placed on its feet.

Darkroom Tent (Item # 96175):
The Tent has been designed for usage particularly at mobile hospitals where it is expected that it will be needed both with the mobile operating section and with the hospitalization section. Its design is such that it can be erected indoors in any room (8 by 10 feet in area and 8 feet in height) as well as within a tent or dugout or by itself, in the open. It is therefore quickly adaptable for use in a temporary building or any building taken over for service as an Evacuation Hospital. It may even serve a purpose at a General Hospital, though at this installation it is more likely that substantial darkroom construction will be had.

Its design includes a two-way adaptation for roentgenoscopy and / or for film processing. It provides for a quick changeover where lightproof conditions are essential. When erected outdoors, additional support may be obtained by weighting apron with turf, rocks or other heavy ballast. Further support may be provided by utilizing auxiliary guy ropes. The guy ropes are not included with the item, but eyelets are provided. The Tent is otherwise supported by means of a sectional frame, which is contained within a specially-designed Chest.
X-Ray Machine and Table Unit (Item # 96215):
This unit has been designed primarily for horizontal roentgenoscopy, horizontal roentgenography and roentgenoscopic localization of foreign bodies. The equipment is so-designed that it can be packed into three lightweight chests for ease of transportation across difficult terrain. The packing arrangement is ingeniously provided for in order to accommodate all the component parts of the equipment. To simplify assembly, printed identifications and color codes are provided on all parts. The Unit consists of the table component, shockproof head and supporting hanger, control, and automatic protective and auxiliary devices. A spare parts compartment for tools and miscellaneous parts is provided in the Control Unit. A spare tube is also provided as a component of the unit. For roentgenoscopy and foreign body localization, a fluoroscopic screen, depth scale marker and localization dial together with necessary accessories are included.

The generating circuit of the unit may be connected to 100-130 or 200-240 volts, 50-60 cycle alternating current. The Control Unit is compact and it contains all the features incorporated into Item # 96085 with modifications and refinements. The shockproof head includes the tube, high tension transformer, and filament transformer immersed in oil. This arrangement obviates the necessity for shockproof cables. Incorporated within the head is the oil impeller and air circulating motors. In addition, it permits the placement of the shockproof components into one insulated head. The x-ray tube of this unit is accommodated in a separate compartment within the shockproof head so that easy exchange of it can be accomplished without the usual difficulties concerned with removing and replacing transformer oil.

The table portion of the unit is assembled with the use of special tools provided and in accordance with instructions printed on the inside of the lids of the Chests. The table is also provided with a cassette lifting device for carrying out roentgenography.

X-Ray Equipment Literature:

Additional data, descriptions, and use of X-Ray Field Units and Equipment can be found in TM 8-275 "Military Roentgenology", dated January 26, 1943, and TM 8-632 "X-Ray Field Unit, Machine, Chassis & Table, Items 9608508, 9608510, 9609005, 9609010, and 9614500" dated February 1945.

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US Army X-Ray Field Unit | WW2 US Medical Research Centre

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Roentgen rays had already been discovered long before the outbreak of WW2. Wilhelm Conrad Röntgen, a German physicist whose discovery would eventually earn him a Nobel Prize, first produced and detected the rays in 1895 whilst working at the University of Würzburg. At first, the findings were called x-rays; but scientists later referred to them as roentgen rays.

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If you consider every stakeholder in the device, you ensure that there's no chance of your product failing for anybody involved

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She researches optical biosensing in the context of point-of-care treatment applications

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There quicker, cheaper, and more easily mass produced. But what you gain in convenience you sacrifice sensitivity/accuracy.

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Some pros of using rapid response diagnostic tests are that they cost significantly less, travel well and can be used in low resource areas without the need for significant infrastructure including electricity or access to the internet. Cons of using rapid diagnostic tests include that they have lower specificity and sensitivity which can lead to treatment problems or misdiagnosis.

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Researchers created a paper-based 3d microfluidic POC device that can be used to diagnose whooping cough. It falls in the "lab on chip" category and uses isothermal dna amplification (which is reported to be a sensitive as PCR) despite how compact it is. The traditional machines used to detect this condition can cost up to $50,000, but this new alternative only costs a few dollars each.

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The magnetic bead-quantum dot immunoassay that I presented last Friday is extremely interesting. It was developed around 5 years ago by Chloe Kim, Gwendolyn Hoffman, and Peter Searson to detect the incidence of malaria via P. falciparum histidine-rich protein 2 with improved sensitivity. One of the most interesting features of the device is the use of quantum dots instead of fluorophores since they don't photobleach and have a much greater quantum efficiency.
https://pubs.acs.org/doi/full/10.1021/acssensors.7b00119

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Integrated Magnetic Bead–Quantum Dot Immunoassay for Malaria Detection

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Malaria persists as a disease of high morbidity and mortality due to improper diagnosis, overuse of drugs, rapidly evolving drug resistant parasites, and poor disease monitoring. The two common tests used in developing countries, microscopic examination of Glemsa slides and rapid diagnostic tests (R…

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It is important to consider all stakeholders when designing a product in order to maximize its effectiveness. If you overlook any group, whether it be the patients, clinicians, investors, or regulatory agencies, it can negatively affect the success of your product and greatly reduce its reach.

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Dr. Locke's research focuses on using optical biosensing for point-of-care monitoring and diagnostics mainly regarding diabetes, preeclampsia, oral cancer, and cardiovascular diseases.

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Pros: quick diagnostic time, inexpensive, more convenient/portable/require less specialized equipment, and typically don't require highly trained personnel
Cons: generally low sensitivity and/or specificity, misdiagnoses are more prevalent

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Considering all stakeholders is important because each affects the overall success of the product. Focusing on just one stakeholder might dissatisfy or hurt other stakeholders, which might hinder the successful launch or sales of the product. Also, each stakeholder covers a unique part of the design process (ideation, regulatory approval, R&D, funding, etc.), so researchers must make sure that all of these areas are adequately covered.

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Dr. Locke's research focus is optical biosensing for point-of-care monitoring & diagnostics. The diseases that she focuses on include oral cancer, diabetes, and pre-term birth.

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Researchers at UC San Diego developed a CRISPR-based diagnostic tool for detection of the SARS-CoV-2 virus. I found this diagnostic tool interesting because it's the first of its kind to use the Cas13d enzyme. I liked how they were exploring different enzymes instead of just sticking to the ones that have already been explored. The researchers actually mentioned that this is key to maximizing CRISPR's capabilities. Using this approach, the tool can deliver accurate results in less than an hour.
https://ucsdnews.ucsd.edu/pressrelease/researchers-develop-crispr-based-rapid-diagnostic-tool-for-sars-cov-2

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Researchers Develop CRISPR-based Rapid Diagnostic Tool for SARS-CoV-2

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Blending experts from molecular genetics, chemistry and health sciences, researchers at the University of California San Diego have created a rapid diagnostic technology that detects SARS-CoV-2, the coronavirus that causes COVID-19.

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Pros: quick turnaround, easy to use, low cost, convenience

Cons: lower sensitivity and accuracy compared to more expensive equipment, chance of misdiagnosis leading to unnecessary or improper treatment

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The BD FACSPresto System is a portable device for monitoring CD4 lymphocyte levels and total hemoglobin concentration in individuals with HIV. The system can deliver results in 22 minutes. This study found the test to perform to an identical standard as the typical laboratory test method. What I found most interesting about the device is that operation of it is language-independent touchscreen interface that display everything via images so anyone can operate it. It also has a built in battery to ensure operation during power interruptions.

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Academic Editor: Raul Colodner

Received: 11 December 2021 / Revised: 20 January 2022 / Accepted: 30 January 2022 / Published: 2 February 2022

HIV viral load is more reliable tool for monitoring treatment throughout the course of HIV/AIDS, but the test may be expensive in resource-limited settings. Therefore, enumeration of CD4 T-lymphocyte count remains important in these settings. This study evaluated the performance of BDFACSPresto, a near-patient CD4 counter planned to be used in primary healthcare clinics in Thailand. Results of percent, absolute CD4 count and hemoglobin (Hb) on the FACSPresto were compared with the TriTEST/TruCOUNT/BDFACSCalibur method and a Sysmex hematology analyzer. Phase I of the study was performed in an ISO15189 laboratory. Both percentage and absolute values showed Passing-Bablok slopes within 0.98-1.06 and 0.97-1.13, mean Bland-Altman biases of +1.2% and +20.5 cells/µL, respectively. In phase II, venous and some capillary blood samples were analyzed in four primary healthcare clinics. The results showed good correlation between capillary and venous blood. For venous blood samples, regression lines showed slopes of 1.01-1.05 and 1.01-1.07 for all percentage and absolute values. The overall mean biases were +0.9% and +17.0 cells/µL. For Hb, Passing-Bablok regression result gave slope within 1.01-1.07 and mean bias of −0.06 g/dL. Thus, CD4 enumeration in blood by the FACSPresto is reliable and can be performed to an identical standard at primary healthcare clinics. View Full-Text

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Figure 1

Sukapirom, K.; Matchua, S.; Thepthai, C.; Srimark, N.; Khowawisetsut, L.; Pattanapanyasat, K. Performance Evaluation of BD FACSPresto TM Near-Patient CD4 Counter for Monitoring Antiretroviral Therapy in HIV-Infected Individuals in Primary Healthcare Clinics in Thailand. Diagnostics 2022, 12, 382. https://doi.org/10.3390/diagnostics12020382

AMA Style

Sukapirom K, Matchua S, Thepthai C, Srimark N, Khowawisetsut L, Pattanapanyasat K. Performance Evaluation of BD FACSPresto TM Near-Patient CD4 Counter for Monitoring Antiretroviral Therapy in HIV-Infected Individuals in Primary Healthcare Clinics in Thailand. Diagnostics. 2022; 12(2):382. https://doi.org/10.3390/diagnostics12020382

Chicago/Turabian Style

Sukapirom, Kasama, Somrat Matchua, Charin Thepthai, Narinee Srimark, Ladawan Khowawisetsut, and Kovit Pattanapanyasat. 2022. "Performance Evaluation of BD FACSPresto TM Near-Patient CD4 Counter for Monitoring Antiretroviral Therapy in HIV-Infected Individuals in Primary Healthcare Clinics in Thailand" Diagnostics 12, no. 2: 382. https://doi.org/10.3390/diagnostics12020382

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Performance Evaluation of BD FACSPrestoTM Near-Patient CD4 Counter for Monitoring Antiretroviral Therapy in HIV-Infected Individuals in Primary Healthcare Clinics in Thailand

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HIV viral load is more reliable tool for monitoring treatment throughout the course of HIV/AIDS, but the test may be expensive in resource-limited settings. Therefore, enumeration of CD4 T-lymphocyte count remains important in these settings. This study evaluated the performance of BDFACSPresto, a near-patient CD4 counter planned to be used in primary healthcare clinics in Thailand.

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it is important to think of all stakeholders through the process because each have a different viewpoint and first hand experience that may inform your design. The needs of each set of stakeholders must be met so that each part of the design  process can be completed, from FDA clearance to manufacturing to patient use.

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Dr Locke is working to develop optical biosensing point of care diagnostics for low resource settings that can monitor diabetes, cardiac disease, and pre-term births. Her previous work in graduate school focused on an optical biosensing implantable device and smartwatch to monitor blood glucose

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Rapid diagnostic tests are much cheaper and faster than alternatives. Patients only have to make one trip to the nearest hospital or clinic to get a diagnosis. This saves time and money for patients that would otherwise need to make multiple trips or receive results via unestablished mail systems. While the tests do not require highly trained medical professionals, those reading the tests do need some training in order to avoid misdiagnosis. The tests are also less sensitive than those done with lab equipment.

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To make your design successful, you need all of your stakeholders on board. You need support from regulators, investors, physicians, and consumers. They all serve as gatekeepers to the success of your product, and if any one of those parties fails to see the usefulness or robustness of your design, you cannot move forward. The other groups may then also withdraw support.

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As a graduate student, Dr. Locke focused on developing a non-invasive way to continuously measure blood glucose using a smartwatch and implantable device. She's also working on developing POC diagnostics for patients with gut diseases and oral cancers.

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With cardiovascular disease growing in incidence in developing countries, there's a significant need for more accessible screening technologies. One major risk factor is dyslipidemia, which is easily diagnosed in the U.S. via a blood test, but not in low resource settings. Companies have developed products such as LipidPlus, lipid test strips that can measure cholesterol from only a drop of blood. I think the low quantity of blood needed for this device is really neat, as it allows for CVD screening without requiring a trained phlebotomist.

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The stakeholders (patients, clinicians, safety regulators etc.) have a direct influence on the adoption and success of any medical device. Without thorough stakeholder engagement, it is impossible to fully grasp the issue that is supposed to be addressed. Design should be centered around the needs of the patient population and clinicians while satisfying the requirements that safety regulators set.

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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6281283/

This study details a smartphone-based oral cancer screening device that uses an Autofluorescence Imaging (AFI) and White Light Imaging (WLI) detection technique which involves observing the radial emittance of the oral tissue fluorescence when it is illuminated at light of the wavelength between 400-410nm. These images are sent automatically to a remote specialist for diagnosis however, the interesting thing about this device is the development of a convolutional neural network (CNN) that is pre-trained to identify images that are most likely to have suspicious looking lesions. The sensitivity and specificity for the CNN's evaluation of images was 85.00% and 88.75% respectively.

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Ross D. Uthoff, Conceptualization, Formal analysis, Investigation, Methodology, Resources, Software, Writing - original draft, Writing - review & editing,#1,* Bofan Song, Conceptualization, Formal analysis, Investigation, Methodology, Resources, Software, Writing - original draft, Writing - review & editing,#1,* Sumsum Sunny, Conceptualization, Investigation, Methodology, Resources, Writing - review & editing,#2, 3 Sanjana Patrick, Investigation, Resources, Writing - review & editing, 4 Amritha Suresh, Investigation, Resources, Writing - review & editing, 2, 3 Trupti Kolur, Investigation, Writing - review & editing, 2 G. Keerthi, Investigation, Resources, Writing - review & editing, 5 Oliver Spires, Investigation, Resources, 1 Afarin Anbarani, Investigation, Writing - review & editing, 6 Petra Wilder-Smith, Conceptualization, Investigation, Methodology, Project administration, Supervision, Writing - review & editing, 6 Moni Abraham Kuriakose, Conceptualization, Funding acquisition, Methodology, Project administration, Supervision, Writing - review & editing, 2, 3 Praveen Birur, Conceptualization, Funding acquisition, Investigation, Methodology, Project administration, Supervision, Writing - review & editing, 4, 5 and Rongguang Liang, Conceptualization, Funding acquisition, Methodology, Project administration, Supervision, Writing - original draft, Writing - review & editing 1,*

Kristen C. Maitland, Editor

Abstract

Oral cancer is a growing health issue in a number of low- and middle-income countries (LMIC), particularly in South and Southeast Asia. The described dual-modality, dual-view, point-of-care oral cancer screening device, developed for high-risk populations in remote regions with limited infrastructure, implements autofluorescence imaging (AFI) and white light imaging (WLI) on a smartphone platform, enabling early detection of pre-cancerous and cancerous lesions in the oral cavity with the potential to reduce morbidity, mortality, and overall healthcare costs. Using a custom Android application, this device synchronizes external light-emitting diode (LED) illumination and image capture for AFI and WLI. Data is uploaded to a cloud server for diagnosis by a remote specialist through a web app, with the ability to transmit triage instructions back to the device and patient. Finally, with the on-site specialist's diagnosis as the gold-standard, the remote specialist and a convolutional neural network (CNN) were able to classify 170 image pairs into 'suspicious' and 'not suspicious' with sensitivities, specificities, positive predictive values, and negative predictive values ranging from 81.25% to 94.94%.

1 Introduction

Oral cancer incidence and death rates are rising in low- and middle-income countries (LMIC) [ 1- 5]. As of 2012, 65% of new oral cancer cases and 77% of oral cancer deaths occurred in LMIC [ 6] with a five year survival rate under 50% in some countries [ 7].

Oral cancer development is increased by a number of lifestyle choices including tobacco [ 8, 9] and alcohol use [ 10]. Particularly in Asia, betel quid (or paan) chewing (with or without tobacco [ 11, 12]) increases rates of oral squamous cell carcinoma (OSCC) and oral submucous fibrosis (OSMF) [ 13- 21]. Betel quid (typically consisting of betel leaf, areca nut, slaked lime, and possibly tobacco [ 22]) was identified as a contributer to increased oral cancer incidence as early as 1902 [ 23]. Despite the risk of developing oral cancer, psychostimulating qualities keep betel quid popular [ 22, 24- 26].

High-risk populations living in remote areas with limited access to healthcare infrastructure are in need of low-cost, easy-to-use medical imaging devices to enable early diagnosis with increased sensitivity as early diagnosis is well correlated with higher survival rates [ 7]. Conventional visual examinations achieve sensitivities around 60% with specificity over 98.5% [ 27] but require visible lesions, possibly delaying diagnosis.

Autofluorescence imaging (AFI) is an alternate detection technique using changes in the radiant exitance of oral tissue fluorescence when illuminated at 400-410 [ 28- 30] to discriminate potential oral malignant lesions, removing the requirement of the lesion being visible [ 19, 28, 31- 41]. Increasing dysplasia results in a decreased fluorescence signal from changes in endogenous fluorophores and increased absorption from hemoglobin [ 29, 33, 34, 42- 44]. Carcinogenesis affects cellular structure, breaking down the collagen and elastin cross-linking, leading to reduced fluorescence signal [ 29, 33, 35, 44]. Additionally, changes in mitochondrial metabolism decreases fluorescence from flavin adenine nucleotide (FAD) [ 43]. Increased microvascularization results in higher hemoglobin content [ 42, 45], increasing absorption of both excitation and emission wavelengths [ 46]. Lastly, in addition to decreased green wavelength fluorescence, a 635 nm emission peak occurs due to increased porphryin take-up in cancerous cells [ 47, 48] with the ratio of signal between 635 nm and 500 nm indicating possible cancerous lesions [ 30, 39, 40].

Previous autofluorescence imaging (AFI) system studies have typically achieved sensitivities of greater than 71% and specificities of 15.3%-100% [ 30, 42, 49- 54] though a few studies have achieved sensitivities of only 30%-50% [ 45, 55]). Increased sensitivity will lead to earlier diagnosis of oral cancer, enabling prompt treatment of the disease, while the specificity of an AFI device needs to remain high to avoid unneeded, invasive biopsies.

In high-risk, remote populations with low doctor-to-patient ratios, the ideal AFI system is operable by any frontline health worker in primary health centers, dentists, nurses, or by any community member, even those without formal healthcare training. In the cases where a trained specialist is not present, a remote specialist can be integrated into the clinical environment through the internet, allowing for informed diagnosis. Smartphones provide portable image collection, computation, and data transmission capabilities controlled by a simple touchscreen interface, addressing the needs of a cancer screening device being simple to use and connected to the internet. Using the smartphone's data transmission capabilities, the collected data can be uploaded to a cloud server, where a remote specialist can access the images and make a diagnosis. Additionally, deep-learning tools like a CNN can be implemented in the cloud and used for automatic image analysis and classification [ 56].

2 Materials

2.1 Hardware

To address the need for oral cancer screening in high-risk populations, we have developed a low-cost, point-of-care smartphone-based system (). The dual-view, oral cancer screening device augments a commercially available Android smartphone (LG G4, LG, Seoul, South Korea) for AFI and white light imaging (WLI) both internal to the oral cavity with an intraoral probe, and external with a whole mouth imaging module [ 57]. The whole cavity imaging module provides a wide field of view (FOV) image for assessment of the patient's overall oral health.

The intraoral probe's custom optical system (Figs and ) extends the entrance pupil away from the smartphone camera aperture and allows for close-focus imaging of the oral tissues. A hygienic sleeve (TIDI Products, Neenah, WI) is used with the intraoral probe for infection prevention. Smartphone cameras are well-designed to capture a wide field of view from a relatively long distance away, and modifying this optical system to (a) decrease the field of view by ∼90%, (b) focus on a close object, (c) utilize the entire image sensor, and (d) yield a packaged design to fit comfortably in the oral cavity and access base of tongue and cheek pockets is challenging. During the design process, the lenses of the smartphone camera were modeled as a single paraxial surface to ensure compatibility with any smartphone camera whose camera can be set to infinite focus. The prescription of the optical system is provided in . The sag of the aspheric surfaces is defined using an even polynomial [ 58]

where r is the radial distance from the optical axis, c is the curvature (1/ R), k is the conic constant, and the α's define the coefficients of the even r-polynomial. The lenses were designed using poly(methyl methacrylate) (PMMA) and OKP4HT (Osaka Gas Chemicals, Osaka, Japan) and fabricated using single point diamond turning (Moore Nanotechnology Systems, Swanzey, NH). A rendered sectioned view of the intraoral probe assembly and the manufactured lenses are shown in . A layout of the optical system is shown in and the nominal modulation transfer function (MTF) is provided in .

Table 1

The system utilizes six 405 nm Luxeon UV U1 LEDs (Lumileds, Amsterdam, Netherlands) to enable AFI and four 4000 K Luxeon Z ES LEDs (Lumileds) for WLI and general screening. The LEDs are placed in a plane-symmetrical pattern on either side of the optical axis (Figs and ). In the intraoral probe, the LEDs are angled toward the object plane to increase illumination uniformity. An emission filter (Asahi Spectra, Tokyo, Japan) with a 470 nm cut-on wavelength is installed in the imaging channel for AFI and excitation filter (Asahi Spectra) is installed in front of the violet LEDs to limit output in the passband of the emission filter. The whole mouth module uses the unmodified smartphone camera optics to provide wide FOV imaging and includes both wavelengths of illumination LEDs, with an emission filter for AFI in the imaging channel.

The illumination LEDs are driven with a switching boost voltage regulator (Linear Technology, Milpitas, CA) controlled by a custom Android application (Sec 2.2) through a Bluetooth connected microcontroller unit (MCU, SparkFun Electronics, Niwot, CO). Two 3.7 V 18650 Li-ion batteries (Orbtronic, Saint Petersburg, FL) power the MCU and LED driver. The MCU sets the LED current through a digital potentiometer (Analog Devices, Norwood, MA) and switches between the LED strings using signal voltages applied to MOSFETs. The smartphone application synchronizes the LED illumination with image capture, optimizing the LED on-time, reducing power consumption and generated heat. A block diagram is shown in .

Finally, the phone and electronics are mounted to a low-cost, 3D-printed mechanical structure of VeroBlackPlus RGD875 plastic (Stratasys, Eden Prairie, MN). This structure also provides a universal mount for the interchangeable imaging modules. A simple redesign of the mechanical structure could allow for a variety of smartphone sizes and camera locations on the backside of the smartphone.

2.2 Software

A custom Android application (app) was developed to guide the user through the data collection process. When first opened, the app prompts the user to create a new case ID or select an ID from a previous session, storing all the data from a single patient under the same ID. From the main menu, relevant patient data (age, history of tobacco or paan use, etc.) can be input, AFI and WLI images can be collected and viewed, on-phone image processing can be completed (), or data can be uploaded to the cloud. During image capture, the smartphone uses its Bluetooth connection to communicate with the MCU to synchronize image capture and the LED illumination. After image capture, the images may be viewed within the app or the AFI images processed on the phone using the red-to-green signal ratio [ 30, 59] with a 'suspicious' or 'not suspicious' classification.

The Android Camera2 API [ 60] is used to enable low-level camera control by the app, including exposure, gain, focus, ISO, color conversion, and white balance. The LG G4 device runs Android 6.0 Marshmallow which supports most of the Camera2 API features and the Camera2 API is compatible with Android 5.0 Lollipop and newer allowing 84.7% of Android devices to run the app [ 61]. Additionally, the app could be ported to other popular smartphone operating systems though the device cost could significantly increase.

The patient data, images, and location data (for further spatio-temporal analysis) is uploaded to a cloud server through Wi-Fi and can be remotely accessed anywhere with an internet connection through a web app deployed on the server (). When viewing images, the specialist is presented with original, full-resolution images along with sliders to adjust contrast and brightness. On the same web-page the specialist uses dropdown menus to select a diagnosis from list (normal, lichen planus, leukoplakia, erythroplakia, etc.) and a text box to provide triage instructions to the patient.

The cloud server hosts a virtual machine configured on a Google cloud compute engine to automatically classify uploaded images with a pre-trained convolutional neural network (CNN), determining the likelihood of the presence of suspicious lesions in each image.

A reminder email is automatically sent to the remote specialists whenever a new case is uploaded to the cloud. Once a remote specialist diagnoses a waiting case, a summary report is generated with uploaded data from the smartphone, CNN results, and diagnoses. The reports can be viewed continuously on the web app and also be downloaded to the smartphone through the Android app.

3 Methods

3.1 System characterization

3.1.1 Imaging

Performance of the intraoral imaging system was characterized by (a) measuring the MTF without the smartphone camera, (b) measuring the MTF with the smartphone camera, (c) evaluating the predicted assembled performance with a Monte Carlo analysis, (d) measuring the cutoff frequency, and (e) evaluating the field of view.

The cutoff frequency and field of view of the intraoral probe optical system was validated by imaging a 1951 USAF resolution test chart.

The MTF of the optical system was directly measured using both an Optikos LensCheck (Optikos, Wakefield, MA) instrument and the slanted edge method [ 62, 63]. The LensCheck system directly measures the point-spread function (PSF) of the intraoral lens system without the smartphone camera lens or image sensor and the MTF is calculated from the normalized Fourier transform of the PSF. The slanted edge method was used to measure the entire optical system including the external lens system, the smartphone camera, and the image sensor. The slanted edge method measures an edge-spread function (ESF) of which the derivative is the line-spread function (LSF). The normalized Fourier transform of the LSF is the one-dimensional MTF. The results from multiple regions of interest across the slanted edge in the central field of view were averaged. The spatial frequency limit was then scaled by the limiting spatial frequency of the added intraoral optical system. Both MTF measurements were compared to representative assembled performance of the passively aligned intraoral probe optics modeled using a Monte Carlo analysis in Zemax OpticStudio (Zemax, Kirkland, WA).

Due to the imaging channel emission filter, the color space is distorted. More accurate color representation is important for image evaluation by a remote specialist and is achieved by applying a custom color matrix

defined by a values that maps the camera RGB values to the CIEXYZ color space [ 64]. After imaging a standard 24-patch color checker board (X-Rite, Grand Rapids, MI) with known CIEXYZ values, the A matrix composed of the a coefficients can be calculated by

where T is the matrix of known CIEXYZ values and C is the matrix of measured RGB camera values.

3.1.2 Illumination

The white light and violet light illumination uniformity was measured by imaging a matte white surface without the emission filter in place. For this test, the violet LEDs were replaced with white LEDs with similar radiance characteristics from the same product series (Luxeon Z) to avoid exciting fluorescence from the measurement surface. The uniformity measurements are corrected by the relative illumination (RI) of the imaging system. The RI of the combined intraoral lens system and the smartphone camera was measured using a liquid light guide coupled source diffused by multiple plates of ground glass. The measured uniformity is compared to a non-sequential raytracing model (FRED, Photon Engineering, Tucson, AZ) using LED rayfiles from the manufacturer. Uniformity is quantified using the coefficient of variation ( c) [ 65] on normalized data,

where x is the luminance value of each pixel, is the mean of the pixels in the image, and σ is the standard deviation of the pixel values.

3.2 Field testing and CNN classification

A pilot human subjects study was performed at KLE Society's Institute of Dental Sciences (Bangalore, India), Mazumdar Shaw Medical Centre (Bangalore, India), and the Christian Institute of Health Sciences & Research (Dimapur, India) to demonstrate the feasibility of the oral cancer screening hardware, remote clinical diagnosis workflow, and classification algorithms. This study received institutional review board (IRB) approval from Mazumdar Shaw Cancer Centre (NNH/MEC-CL-2016-394) and University of California, Irvine (HS#2002-2805). All subjects provided informed written and oral consent.

Inclusion criteria included clinically suspicious oral lesions, a history of previously treated OSCC with no current evidence of cancer recurrence at least six months after cessation of treatment, or the presence of recently diagnosed, untreated OSCC or pre-cancerous lesions. Exclusion criteria included being less than or equal to 18 years of age, currently undergoing treatment for malignancy, pregnancy, under treatment for tuberculosis, or suffering from any acute illness.

The full field testing workflow is shown in . When patients arrived for their visit, they first read, understood, and signed a consent form. After acknowledging consent, a general dentist or oral oncology specialist performed a conventional visual oral exam. Following, the general dentist performed the smartphone-based imaging exam, collecting both AFI and WLI with both the whole cavity imaging module and the intraoral probe module. Finally, the oral oncology specialist clinically diagnosed each lesion site, with the clinical diagnosis serving as the gold standard.

Based on the gold-standard diagnosis, the images were assigned to either the normal class or suspicious class. Diagnoses of oral squamous cell carcinoma, lichen planus, homogeneous leukoplakia, speckled leukoplakia, tobacco pouch keratosis, verruccous leukoplakia, and oral submucous fibrosis were included in the suspicious class. Diagnoses of normal/variation were included in the normal class. Variation includes normal variations of oral mucosa, including fissured tongue, Fordyce granules, leukoedema, physiological pigmentation, and linea alba buccalis [ 66- 68]. Diagnoses of benign were not included in either class.

The captured images were uploaded to the cloud server for diagnosis by a remote specialist, and for the intraoral images, classification by the conventional neural network (CNN). Image pairs (WLI and AFI) were screened by the remote specialist for sufficient image quality (minimal motion blur, in focus) to make a diagnosis.

The intraoral images were then classified with a trained CNN. For the CNN training, methods commonly used in network training were applied including transfer learning [ 69] and data augmentation [ 70- 72]. For data augmentation, the original images were rotated and flipped to feed the network more data for training. Additionally, transfer learning was applied by using a VGG-M [ 70] network pre-trained on the ImageNet dataset [ 73]. The network was modified for our task by replacing the final dense layer and softmax layer and then training the network with our dataset.

Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) [ 74, 75] were calculated to compare the remote specialist diagnosis and the CNN result to the gold-standard on-site specialist diagnosis. Lastly, a receiver operating characteristic (ROC) curve was generated to determine the accuracy of the classifier and area under the ROC curve (AUC) calculated to provide a single value for comparison to other devices [ 76, 77].

4 Results

4.1 System performance

4.1.1 Imaging

provides the resulting image of a 1951 USAF resolution test chart, showing a resolution limit of 71.8 lp/mm and also the full field of the view of the intraoral probe.

The measured MTF along with the performance of an average system from the Monte Carlo analysis with representative tolerances is shown in . A sensitivity analysis shows decenter of the outside concave surface of L4, L3 decenter, and L4 decenter have the greatest effect on performance.

Lastly, the color mapping A matrix was calculated to be

4.1.2 Illumination uniformity

Data for the modeled and measured uniformity for the intraoral and whole mouth modules are provided in .

4.2 Field testing and CNN classification

Data was collected at the three testing sites from 190 patients with data from 99 patients (demographics shown in ) used for CNN analysis and remote diagnosis.

Out of 364 image pairs, 170 WLI and AFI image pairs had sufficient quality for remote diagnosis and use in the CNN with N = 86 in the normal class and N = 84 in the suspicious class. Data augmentation increased the dataset size by 8× to 1360 image pairs. After training the network for 80 epochs, four-fold cross validation accuracy of the VGG-M network was 86.88%. The ROC curve for the CNN is provided in and the AUC = 0.908.

Sensitivity, specificity, PPV, and NPV values comparing the remote specialist diagnosis and the CNN result to the gold-standard on-site oral oncology specialist clinical diagnosis are provided in .

Table 4

Sample images diagnosed by a remote specialist are shown in Figs and . shows AFI and WLI taken with the intraoral probe. With suspect areas outlined, the combination of WLI and AFI provides the most information about the type of lesion and the size of the affected area. provides similar findings for the whole cavity imaging module.

5 Discussion

The smartphone platform is a natural progression of previous autofluorescence systems targeting oral lesions [ 34, 41, 42, 78- 83] and our device offers several improvements. Compared to previous smartphone-based systems [ 83], the two FOVs are useful for both an overview of the oral cavity health along with targeted imaging of problem areas. Our intraoral probe extends capability, reaching to the base of the tongue and cheek pockets in some patients, areas of increased cancer risk [ 4]. Our device offers image capture, save, review, and transmit of both AFI and WLI captured both intraorally and externally to the oral cavity. Additionally, our intraoral imaging attachment utilizes a custom designed optical system to maximize the number of pixels used on the smartphone image sensor. Operation of the system is simple through an intuitive user interface. Since the device is connected to the cloud and remote diagnosis is possible, the system does not need to be operated by a specialist, with the remote specialist integrated into the clinical environment through the internet. Importantly, the device implements a machine learning algorithm to aid both the community health workers and the remote specialists as devices requiring the human visual system (HVS) to make decisions based on small changes in scene or image brightness are suboptimal due to the logarithmic response of the HVS [ 84, 85].

The measured imaging performance of the device matches the predicted performance for a passively aligned optical system and is sufficient for an oral cancer screening device, able to resolve features down to 14 μm. Similar to the Monte Carlo result, the measured mid-spatial frequency performance is decreased from the nominal. Contributions to the decreased performance include stray light from various mechanical surfaces, chromatic aberration, and passively aligned lenses. The TIDI Products SureClear Window is specifically designed to minimally affect image quality through the sheath, though the barrier can increase aberrations and specular reflection from the white LEDs when saliva is introduced on the barrier. Image sensor noise and the proprietary image processing pipeline of the smartphone have the opportunity to decrease the resolution cutoff of the optical system. Automatic, immutable image processing implemented by the smartphone manufacturer including edge sharpening could explain differences between the Optikos and slanted edge measured results. Additionally, single-point diamond turning tool marks cause diffraction-type scatter proportional to the power spectral density (PSD) of the surface, diminishing the quality of the PSF [ 86]. Due to the low amount of nominal distortion (<0.8%) in the optical system, distortion is not calibrated to save computation time and power in the system.

The measured and modeled illumination uniformity match well for both modules and illumination wavelengths. The whole cavity module uniformity error is only 2% for white illumination and 1% for violet illumination. For the intraoral probe the error is slightly larger at 7% for white light illumination and 4% for violet illumination. The increase in uniformity from the model is likely due to errors in the scattering properties of the various surfaces in the model, including the system mechanics and the target surface.

Our initial field-testing workflow and results were positive. Through the web app, doctors were able to diagnose cases quickly and efficiently, with the AFI and WLI from two FOVs providing the needed information. Compared to the on-site specialist, the remote specialist was able to correctly diagnose patients as having suspicious lesions with high specificity, sensitivity, and PPV, though the remote specialist's ability to correctly clear patients without suspicious lesions could be improved. The sensitivity and specificity of previous autofluorescence-only devices can have large variation [ 54], while also needing to be operated by a specialist. The combination of AFI and WLI in our device should set the sensitivity floor at 60%, the value for a conventional visual exam [ 27].

The CNN sensitivity, specificity, PPV, NPV, and AUC results are promising given the small size of the dataset, however, future research will need to include benign cases in the training and classification processes. Our AUC value is similar to the high-end of results obtained with similar systems in discriminating healthy tissue from lesions [ 30, 38, 45, 50, 87], however, results have been mixed and the addition of benign lesions decreased the AUC significantly [ 38].

Additionally, a study including biopsy and a histopathology gold standard is needed to fully correlate the CNN result. Importantly for our small dataset, data augmentation increased the number of images pairs by 8×, and since the images have no natural orientation, flipped and rotated images are still valid. As improvements to the device are made and the health providers acquire additional time and training with the device, the dataset size and percentage of quality images will increase, leading to improvements in CNN training. We hope augmenting the WLI with AFI and the CNN classification algorithm leads to true diagnostic performance in line with our reported CNN result.

The main challenges to using AFI and WLI for cancerous and pre-cancerous lesion detection include increased fluorescence signal from hyperkeratinization of pre-malignant lesions causing an increase in autofluorescence signal [ 88] and differentiating between pre-cancerous lesions and areas of inflammation or irritation that can confound either a human or computer diagnosis [ 42], though combining WLI and AFI with longitudinal data discriminates dysplasia from short-term inflammation. The main challenges to large-scale implementation of this device will be addressing the needs of regions without cellular data or internet access and the additional time burden on the remote specialists for diagnosing cases and monitoring lesion progress. However, the overall time burden should decrease as other community members will be able to collect the necessary data.

Improvements for the next generation device could include the addition of a simple mean subtraction from the green channel of the original AFI

to the AFI image already presented to provide the diagnosing specialist with an additional map of areas of decreased fluorescence signal as shown in Figs and . The on-phone red/green ratio image analysis could also be added to the information shown to the remote specialist (and on-site specialist if present during data collection) [ 30]. Additionally, including the whole cavity images in the CNN training and classification would increase the amount of data available, however, these images have many additional noise features such as the perioral epidermis and teeth.

A smaller profile for the intraoral probe would be more effective in accessing sites deep in the oral cavity like the cheek pockets and base of tongue, particularly in patients with advanced oral submucous fibrosis. The remote specialist could be better integrated into the clinical environment with a wider field of view and longer depth of field of the intraoral probe to improve area recognition and image quality, helping to orient the remote specialist during diagnosis. Crossed polarizers for the white light LEDs would reduce noise in the image due to specular reflection. Lastly, as use hours increase, app feedback will be used to further streamline the user experience, making data collection easier for all types of users.

Though the targeted communities lack healthcare infrastructure, many have ample cellular data coverage, and as the cost of smartphones continues to decrease, ownership in LMIC increases (the compound annual growth rate (CAGR) of mobile subscriptions in LMICs since 2008 is 20% [ 89] and the CAGR of smartphone ownership from 2013-2015 is >30% [ 90]). Smartphone-based devices allow for a hub and spoke model where the hub houses the specialists and trained healthcare workers implementing the screening program and the smartphones extend spokes out to the remote communities. A low system cost enables this model and high-volume cost estimates for our system are ~ $100 plus the cost of the smartphone (The cost of the smartphone is not included since most users will be able to use their own smartphone), an inexpensive medical imaging device.

6 Conclusion

Described is the design and implementation of a low-cost, point-of-care, smartphone-based, dual-modality imaging system for oral cancer screening in LMIC. The device enables clinicians and community members to capture AFI and WLI and upload images to the cloud for both remote specialist diagnosis and CNN classification. We have tested the device and diagnosis workflow in three locations in India and initial feedback on the system is positive, with both the remote specialist and CNN achieving high values of sensitivity, specificity, PPV, and NPV compared to the on-site specialist gold standard.

Inexpensive, high-power LED sources in white and violet wavelengths, plastic lens molding technology, and low-cost but powerful smartphones are promising developments for the creation of low-cost, portable, simple-to-use autofluorescence imaging devices for oral cancer detection. Performance should increase as additional images are collected and with improvements to the device hardware and usability. Enabling oral cancer detection in low-resource communities will lead to earlier detection and diagnosis, minimizing disease progression and ultimately, a reduction in oral cancer death rates and healthcare costs.

7 Supplemental material

The design files for the LED driver have been released on GitHub under the GPL-3.0 license [ 91, 92] and the corresponding data repository is found at [ 93].

Acknowledgments

Thank you to Pier Morgan and the Center for Gamma-ray Imaging (CGRI) for use and operation of the rapid prototype printer, and to Ken Almonte for guidance on the design of the LED driver. Thank you to TIDI Products for manufacturing custom shields for our device.

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87. Rahman MS, Ingole N, Roblyer D, Stepanek V, Richards-Kortum R, Gillenwater A, et al. Evaluation of a Low-Cost, Portable Imaging System for Early Detection of Oral Cancer. Head Neck Oncol. 2010;2(10):8. [[ PubMed] PMC free article] [ Google Scholar]

91. Uthoff RD Rossuthoff/Intraoral_led_driver: KiCAD Design Files. GitHub. 2018;.

92. Uthoff RD rossuthoff/Kicad_footprints: Custom Footprints for Pcb Designs. GitHub. 2018;.

93. Uthoff RD rossuthoff/rossuthoff/10.1371-journal.pone.0207493: Data repository for manuscript 10.1371/journal.pone.0207493. GitHub. 2018;.

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Point-of-care, smartphone-based, dual-modality, dual-view, oral cancer screening device with neural network classification for low-resource communities

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Ross D. Uthoff, Conceptualization, Formal analysis, Investigation, Methodology, Resources, Software, Writing - original draft, Writing - review & editing,# 1, * Bofan Song, Conceptualization, Formal analysis, Investigation, Methodology, Resources, Software, Writing - original draft, Writing - review & editing,# 1, * Sumsum Sunny, Conceptualization, Investigation, Methodology, Resources, Writing - review & editing,# 2, 3 Sanjana Patrick, Investigation, Resources, Writing - review & editing, 4 Amritha Suresh, Investigation, Resources, Writing - review & editing, 2, 3 Trupti Kolur, Investigation, Writing - review & editing, 2 G.

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Dr. Locke's research is focused on optical biosensing for point-of-care monitoring and diagnostics for conditions such as pre-term birth, cardiac disease, diabetes and oral cancer

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Rapid diagnostic tests are lower cost, require less training to administer and have faster turnaround time. The cons of them however are their lower specificity and sensitivity as compared to traditional laboratory tests.

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A major advantage of rapid diagnostic tests are that they're easier to use in low-resource settings than are traditional lab tests. Many don't require electricity and can return results during a patient's visit. This is especially important in communities without the internet and telephone infrastructure enabling easy communication of results. The caveat however is that these tests are often less sensitive and less accurate than more expensive, time consuming tests.

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A product cannot be adopted unless people agree to use it at every label. The FDA has to approve it, physicians have to want to use it, insurance has to reimburse it, and patients have to be willing to have it used on them. Securing investments is often essential to production and considering maintenance and disposal help to build your brand with other buyers

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Her main focus is point- of-care monitoring and diagnostics with an emphasis in low resource. Currently she is using biosensing to help treat diabetes, but has also worked with oral cancer, gut function, pre-term births, and cardiac disease

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It is important to consider all of the stakeholders throughout the design process because although a device might meet all of the requirements for correct functionality, it actually has to be used to be solved the problem it is attempting to solve. The stakeholders determine if a device is worth using. Because of this, it is important to gather the opinions, needs and wants of all of the stakeholders.

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Dr. Locke's current research focus is optical biosensing for point-of-care monitoring and diagnostics. She looks into diagnostics for conditions such as diabetes, cancer, cardiac diseases and pre-term birth.

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https://www.ajmc.com/view/cheap-and-easy-to-use-diagnostic-tests-to-detect-disease-biomarkers-including-cancer

One device I found interesting was a low-cost, noninvasie paper test developed by MIT researchers to detect cancer. Urine is placed on a paper lateral flow assay, which uses nanoparticles interaction with protease to potentially detect hundreds of biomarkers. It can be used without trained technicians and does not need any additional equipment to function. Currenlty this raid diagnostic test is being applied to liver function, rapid immunity assessment, child nutrition monitoring, and nucleic acid detection to diagnose Brucella abortus.

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Cheap and Easy-To-Use Diagnostic Tests to Detect Disease Biomarkers, Including Cancer

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These products are usually cheaper, more accessible, don't require physicians, and faster than the alternative. But they often trade off accuracy and they can be confusing to untrained users

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One device that I found interesting was a
cow-side blood β-hydroxybutyrate meter which can be used to measure the ketone bodies present in a cow's blood, which when present in high levels lead to reduced milk yield and increased risk of secondary diseases. I found this device interesting, because it was originally based on a human glucose sensor, but was converted to function for bovine medicine, allowing for whole herd health to be more cheaply monitored rather than sampling a few individuals as representative of the herd due to the cost of laboratory testing for the same measures.

https://www.vetmed.wisc.edu/fapm/wp-content/uploads/2020/01/BHBA-Testing-Update-100208.pdf
https://bvajournals.onlinelibrary.wiley.com/doi/10.1136/inp.i2704

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This researchers from this study created a low-resource paper-based microfluidics device for the diagnosis of malaria. The most interesting thing about this device is it can compare to the accuracy and precision of PCR laboratory assays while providing high quality and rapid diagnosis of malaria at high sensitivity and specificity (detected 98% of infected people in a double blind study). The study also provides hope that high quality assays that are comparable to the gold standard (i.e. PCR) can be implemented in low-resource environments.
https://www.pnas.org/content/116/11/4834

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Device Design and Fabrication.

The paper origami device for DNA extraction was fabricated using an inexpensive hot wax printing method ( Fig. 1A), with adaptations to published methods ( 25, 27). The folding-based, sample-processing steps are illustrated in Figs. 1 and 2 (and are also detailed in Movie S1). The lateral flow component of the assay was designed in the University of Glasgow and was fabricated by Ustar ( 28).

A finger-prick blood sample was added to an RDT, to an Eppendorf tube, to a "fast transient analysis" (FTA) card (for retrospective analysis with PCR amplification assays), and to glass slides for thick smears using Giemsa staining and optical microscopy. The same blood was used immediately (before clotting, <2 min) for the microfluidic paper test. Ten microliters of lysis buffer containing magnetic beads was added to 5 µL of blood. After 5 min, a further aliquot of binding buffer was added, and the DNA was captured on the beads, which were transferred to the sample zone of the folded (origami) paper device ( Figs. 1A and 2B) as a 40-µL volume. All residues were then washed off manually by dispensing a volume-independent aliquot of a washing buffer onto the sample reception area; excess buffer and residues were then drained away under capillary force by folding the reception panel against a waste panel ( Figs. 1A and 2B).

The bead-bound DNA was retained within the paper matrix, which was then refolded against distributing channels ( Fig. 2 C and D) before elution buffer was added. Within the distribution channel, the sample was split into three spots (as a multiplex), which themselves then formed the independent LAMP chambers ( Fig. 1A, arrow 5). The sample-preparation processing requires two manipulations, namely, the addition of washing and elution buffers, a procedure easily performed by local healthcare workers.

In two of the chambers, DNA from Plasmodium pan and P. falciparum were tested, while a separate chamber was used as a control. The device was sealed with an acetate film to prevent evaporation during the LAMP reaction at 63 °C for 45 min on a hot plate, or in a water bath, heated on a cooking stove. If Plasmodium DNA is present in the sample, a specific LAMP reaction takes place in which amplicons are generated with both biotin- and FITC-labeled primers, as a complex bearing two ligands (see SI Appendix, Fig. S1, which illustrates how the lateral flow assay works and how its results are visualized).

Following the LAMP reaction, the test sample was then transferred to the lateral flow strips ( Fig. 1, location 2) using a finger pump ( 29). The buffer moves the products of the LAMP reaction laterally into the detection strips, and the assay proceeds under capillary flow. In this way, the vertical sample-processing steps of the origami device were integrated into a lateral flow-mediated amplification and visual readout system. The detection strips contain anti-FITC antibodies and immobilized streptavidin in the test and control lines, respectively. This detection step takes less than 1 min, and results were analyzed by eye (SI Appendix, Fig. S1). When the complex, generated by the LAMP assay flows through the lateral flow detection device, the species-specific ligands are captured to generate appropriate lines as a positive result (SI Appendix, Fig. S1), with the nanoparticle-bound ligands concentrated at the band.

If target DNA was not present in the sample and no amplification had taken place, then only biotin−streptavidin conjugation occurs, which results as a single red line indicating a negative result (SI Appendix, Fig. S1). In addition to a control line to show that the lateral flow device worked, the diagnostic device also included a positive control, consisting of a BRCA1 target amplified from artificial DNA targets as lane P, as a quality control step (to rule out false negatives due to test failure in challenging environmental conditions, such as high humidity and heat).

Laboratory-Based Characterization.

As stated, we first verified the sensitivity of the LAMP assay used in this device in a laboratory setting in the United Kingdom, using a serial dilution of the WHO International Standard for P. falciparum DNA ( 30). Fig. 3A shows the test results in the form of the test strips that were generated, together with a quantification of the intensities of the test line to validate the visual analysis (see Materials and Methods for details). The analytical sensitivity of the Plasmodium pan assay, which detects several Plasmodium species (including P. falciparum, P. malariae, P. vivax, and P. ovale), was 10 5 IU/mL after 45-min amplification. The P. falciparum assay detected this species (alone) with a similar level of sensitivity as the Plasmodium pan assay ( Fig. 3C), in agreement with previously performed laboratory-based assays, such as commercially available LAMP kits ( 31).

We also evaluated the performance of rehydrated amplification enzymes after storage at room temperature. Freeze-dried enzymes are commercially available in large batches, but, once rehydrated, their stability becomes a key concern for the application of NAATs in resource-limited areas, since there is limited availability of cold storage facilities ( 32). We stored rehydrated LAMP mixtures under three different conditions (−20 °C, 4 °C, and at room temperature, i.e., ∼22 ± 2 °C) for 72 h, and measured their activity every 12 h, using a target concentration of 10 5 IU/mL, by real-time PCR and by using the DNA detection strip used in the microfluidic device ( Fig. 4 A and C). The results demonstrated that rehydrated enzymes stored for 3 d at room temperature showed no significant decrease in performance ( Fig. 4B), supporting the use of these commercially available kits for field-based trials, where cold storage is unavailable.

We repeated this experiment after the field study in Uganda, using a sample of freeze-dried enzyme that was brought to Uganda, stored there at local room temperature ( ca. 20 °C to 35 °C) and brought back to the United Kingdom. SI Appendix, Fig. S4 shows that the rehydrated LAMP reagent is stable after a day of storage at temperatures up to 40 °C.

Materials and Reagents.

Deionized water (DI H 2 O) with a resistivity of >18 MΩ·cm was used to prepare all aqueous solutions transported from the United Kingdom. Fresh bottled drinking water was purchased locally and used for washing glassware and, for example, preparing Giemsa stains. Unless otherwise specified, all other reagents were purchased from Sigma-Aldrich.

Multiplex LAMP System.

The primer sets used for the LAMP assay were based on previously published primer sequences for P. falciparum ( 45), and Plasmodium genus ( 31). A LAMP assay that amplified a BCRA1 gene fragment served as a positive control ( 46). The primers were all purchased from Eurofins Genomics. The sequences are provided in SI Appendix, Table S1. The 20-µL LAMP reaction contained 0.5 µM inner primers (forward inner primer and backward inner primer), 0.1 µM outer primers (F3 and B3), and 0.4 µM loop primers, labeled with Biotin and FITC at their 5′ ends. The reaction mix also contained 0.4 mM of each dNTPs (Sigma), 4.0 mM MgSO 4, 50 mM Tris⋅HCl (pH 8.1), 30 mM KCl, 30 mM (NH 4) 2SO 4, 0.1% Triton X-100, 1 M Betaine, and eight units of Gsp SSD 2.0 DNA polymerase (freeze-dried; OptiGene). The multiplex LAMP reactions were performed at 65 °C for 45 min.

Paper-Based Microfluidic Device.

The fabrication of the device was performed, without specialized facilities or a clean room, simply by using a wax printer (Xerox ColorQube 8570) ( 27, 47) and a hot plate. Each device contained a filter paper-based fluidic device where the extracted DNA and the sample liquid were constrained by printed hydrophobic wax (cat# 108R00935; Xerox).

The filter paper was first printed with the wax using the wax printer, then heated at 120 °C for 1 min to 1.5 min on the hot plate to melt the printed wax. The melted wax diffused through the filter paper, thus forming the same hydrophobic pattern of channels on both sides. Subsequently, the glass fiber spots (3 mm in diameter; Whatman) were manually positioned, such that, when the paper was appropriately folded, the reagents and extracted DNA could be transferred to the spots. After adding the LAMP master mix, the plastic device was sealed using an acetate film, preventing liquid evaporation during amplification.

Lateral Flow Test.

The plastic devices containing finger pumps and lateral flow strips ( Fig. 1) for field testing were manufactured by CNC machining at Epigem Ltd. The dimensions are provided in SI Appendix, Fig. S5. A single-sided adhesive acetate film (MicroAmp Optical Adhesive Film; Thermo Scientific) sealed the plastic device plate with the LAMP reaction chambers, which contained glass fiber spots that received DNA from the paper fluidic device.

Quality Control.

Air bubbles, generated during assembly of the paper strips onto the plastic case, can lead to critical failure during processing. All devices were inspected carefully for such air gaps and discarded if gaps were present. This process was repeated before each assay. As stated, the devices' designs were fully characterized in a laboratory setting before field use, with no subsequent additional quality check performed in the field.

As stated, we stored rehydrated LAMP mixtures under three different conditions (−20 °C, 4 °C, and at room temperature, i.e., ∼22 °C) and checked their stability both by PCR and by using the DNA detection strips, to show that rehydrated enzymes can be stored for 3 d at room temperature (as cold storage was not available). The use of both a positive control for the LAMP reaction and a control line in the lateral flow assay enabled the validation of results in the field.

Study Design.

The aim of this study was to demonstrate the performance of an origami-lateral flow format, combining simple sample processing with easy visualization of results. One additional objective was also to demonstrate the potential role of multiplexed species-specific diagnosis from whole blood finger pricks in rural, underserved communities. The diagnostic strips were used to test blood samples collected from 67 school children from Bukagabo Primary School, in the St. Kizito region, and Mayuge and Apac District School, Apac region. The sample size was calculated to provide enough samples for a clear evaluation of sensitivity (with a power of >0.8 and P value of <0.05 for a target sensitivity of >90%, yielding >30 positive samples), while, at the same time, taking into account the practical limitation of carrying out the test (limiting the numbers to 10/d to 20/d). Given the high prevalence (expected above 70% based on epidemiological data, but, in practice, often >90% in our study), we were not able to test for specificity ( 48).

This study was conducted with the Vector Control Division of the Ministry of Health in Kampala, Uganda, on neglected tropical diseases, and was approved by the Vector Control Division Research and Ethics Committee, VCDREC/078, and Uganda National Council for Science and Technology (HS 2193). School children between the ages of 6 y and 14 y were recruited as a cohort (balanced for sex) under the supervision of their class teachers. Each child was assigned a unique identification number (ID), and their age, sex, name, parents' name (to ascertain consent), and school class were recorded. Details without names were computerized and anonymized using the ID numbers. No personal data were revealed to the investigators. Written informed consent of the parents and the head teacher were also obtained.

The parents/guardians were informed of the activities by the head teacher at community meetings, and their verbal and written assent for their children's participation was obtained. Where parents were unable to write, their fingerprint was used as a signature (see SI Appendix. photos ESI-1 and ESI-2). After testing, all patients were treated as malaria cases and given antimalarial therapeutics, including cases that tested negative on site. This follows guidance in the ethical approval obtained, given that all samples were retested by PCR in the United Kingdom retrospectively, a method that is more sensitive than the ones available onsite.

Ministry of Health Vector Control Division healthcare workers collected all blood samples as finger-prick samples (<50 µL) either in 1.5-mL Eppendorf tubes [for field reference methods, i.e., for Giemsa staining (see SI Appendix, photo ESI-3) and microscopy, for CareStart Malaria RDTs (see SI Appendix, photo ESI-4), or for storage on Whatman FTA (see SI Appendix, photo ESI-5) classic cards and retrospective PCR analysis in the United Kingdom] or for being placed on the paper device; see Microfluidic Testing for all details. As stated, all samples were anonymized with an ID. Microfluidic testing, Giemsa staining, and microscopy as well as diagnostic assessment with the RDT were all carried out within the same school classrooms in parallel to testing on the paper-based microfluidic device without sample storage. Testing was double-blinded between on-site and reference tests. After testing at the school, all used paper devices and small plastic consumables were incinerated by burning on a bonfire, while glass slides and RDTs were stored in a biohazard container for safe disposal at the Vector Control Division, Kampala (SI Appendix, photo ESI-6).

We also provide data from a separate study of 20 negative samples, in SI Appendix, Fig. S2, obtained in September 2018 from Adicon clinical laboratories (Hangzhou, China) and validated on PCR. Five milliliters of whole blood was obtained from patients using routine phlebotomy in a vacutainer, coated with heparin. The blood was stored in a fridge until use (for less than 8 h). Five microliters of the sample was taken out of the tube and used on the paper device, while 200 µL was processed for PCR (see Real-Time PCR). This latter work was performed in a laboratory and in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. All procedures were carried out in accordance with Measures on Ethical Review over Biomedical Research Involving Human Subjects ( 49). All of the samples were collected from patients after obtaining informed consent, and the data from these patients were used in this study only.

Microfluidic Testing.

In practice, three assays were typically run in parallel as a triplex, which required ∼45 min to complete. All analysis was performed in the children's classrooms. Five microliters of human whole blood was pretreated with 1 µL of proteinase K (20 mg/mL; Thermo) and 10 µL of lysis buffer (4 M GUSCN, 25 mM sodium citrate, 0.2% SDS) in a 1.5-mL Eppendorf tube and incubated at 60 °C for 5 min with 10 µL of cell lysis buffer, and 1 μL of MagaZorb beads (diameter 4.5 μm) (Promega). Twenty microliters of binding buffer (from MagaZorb kit; Promega) was mixed with the sample and incubated at room temperature for 5 min. A 40-µL volume of the resulting homogenous mixture was then added to the sample zone ( Fig. 2B). The beads remained at the surface of the sample zone while residues were washed away to the waste pad through the filter paper.

The magnetic beads were washed with volume-independent washing buffer (from MagaZorb kit; Promega) twice. The device was then folded to bring the sample zone into contact with the distributing channel, before 40 µL of elution buffer (100 mM TE buffer, pH 8.0) was added to elute the DNA. The eluted DNA was then guided to three different locations on the paper within the wax-printed channel and transferred by capillary action to their respective reaction chambers in the plastic device by making contact with a paper pad inserted into the plastic chamber. The folded paper was then torn away and incinerated for safe disposal. The independent chambers were sealed with an acetate film to prevent liquid evaporation during the isothermal amplification, following the addition of 16 µL of species-specific LAMP reagents.

The LAMP isothermal reaction ( n = 59) was performed on an electric-powered hot plate, although, to demonstrate that the assay could be performed without electric power, a small number ( n = 8) were amplified in a water bath, using a pan on a local cooking stove. The temperature of the assays was maintained at around 63 °C by racking the chips in a metal block with a high thermal heat capacity (sitting in water) and, when necessary, controlling the distance between the pan and stove (see SI Appendix, photo ESI-7). Temperature variations were ±3 °C around the target temperature. As previously stated, and in all cases ( n = 67), at the end of the incubation, the running buffer chambers (1 in Fig. 1) were manually pressed to enable the buffer to push the LAMP reaction mix onto the lateral flow device, as previously published ( 28), manufactured by Ustar Biotech Co., Ltd. Microfluidic DNA test strips were imaged using an iPhone 6 camera on automatic setting, as a digital record. No postprocessing was required for line intensity analysis and diagnosis. SI Appendix, photo ESI-8 shows an example of such a strip.

Notwithstanding this, the intensities of the test and control lines were analyzed and measured using ImageJ ( 50), and the intensity of the control line (in the red channel) was divided by the intensity of the test line for each strip to obtain the percentage intensity of the control line for each test ( 51).

Thick Blood Smears, Giemsa Staining, and Microscopy.

Optical microscopy was performed by trained technicians working for the Vector Control Division of the Ministry of Health, Kampala. All healthcare workers were qualified and all had >2 y of experience of field microscopy. SI Appendix, photo ESI-3 shows Giemsa staining and microscopy, with testing performed in the school classrooms at the same time as microfluidic testing and RDT analysis. For the thick film stain, a drop of blood from the finger prick was placed at the center of a glass slide and spread as a smear. The slide was allowed to dry under ambient conditions for 20 min and was then stained with 10% Giemsa stain for a further 10 min.

Smears were examined under a compound microscope (made in Philippines; Model CX21FS1; Olympus Corporation) using a 100× oil immersion objective lens, with either electrical or natural light sources (depending upon availability). Malaria parasites were counted against 200 white blood cells (WBCs) and multiplied by factor 40 to give a parasitaemia per microliter of blood (in 1 µL of blood) ( 52).

RDT Analysis.

As stated, CareStart Malaria RDTs, provided by the Ministry of Health, were used as a field reference technique, performed in the school classrooms (see SI Appendix, photo ESI-4) at the same time as microfluidic testing and thick film smears. We used the One step Malaria HRP-II ( P. falciparum) and pLDH ( P. pan) Antigen Rapid Test (SD Bioline Malaria Ag) P. falciparum/ Plasmodium pan test kit as a qualitative test method of detecting species-specific Plasmodium of P. falciparum and Plasmodium pan ( P. vivax, P. malariae, or P. ovale) antigens in the individuals' blood.

A finger prick of blood (5 µL) was transferred from the child's finger to the circular sample well. Four drops of CareStart assay diluent were then added into the square assay diluent well, and the test device was allowed to stand for 20 min (for capillary flows to enable the immunodiagnostic binding). A positive P. falciparum was indicated by the presence of two colored bands (" P. falciparum" test line and "C" control line) or three colored bands (" P. falciparum" and " Plasmodium pan" test lines and "C" control line) within the result window. Positive for other Plasmodium species ( P. vivax, P. malariae, or P. ovale) was indicated by the presence of two colored bands ("pan" test line and "C" control line) within the result window regardless of which band appears first. Mixed infections of P. falciparum and P. vivax (or P. malariae and P. ovale) were indicated by the presence of three colored bands (" P. falciparum" and " Plasmodium pan" test lines and "C" control line) within the result window regardless of which band appears first. No malarial infection was indicated by one line "C" in the result window [2015 One Step Malaria HRP-II ( P. falciparum) and pLDH (pan) Antigen Rapid Test "SD BIOLINE Malaria Ag P.f/Pan test kit"; Standard Diagnostics, Inc.; https://www.alere.com/en/home/products-services/brands/sd-bioline.html].

Dried Blood DNA Extraction.

Finger-prick whole-blood samples were spotted on FTA classic cards (Whatman) directly after bleeding, air-dried completely, and, on return to the Vector Control Division, Kampala, shipped with a desiccant at ambient temperature. Upon arrival in the United Kingdom, they were stored at −20 °C until used. Three-millimeter sample discs from the dried sample spot were removed using a disposable punch and placed in a clean tube. Three hundred microliters of PBS was added to the tube, which was then incubated at room temperature for 2 h, after which time 20 μL of protein K was added, and the sample was incubated at 56 °C for 1 h. The samples were further processed following the instructions from the MagaZorb DNA Mini-Prep Kit (Promega) and eluted with 50 μL of elution buffer. The extracted samples were coded randomly and dispensed in a 96-well plate together with 10 negative (water) samples added at random.

Real-Time PCR.

The 18S rRNA gene subunit-based Plasmodium sp. screening real-time PCR and P. falciparum species-specific real-time PCR provided the reference standard for assessing the diagnostic performance of the paper-based microfluidic device reported in this program of work ( 6). The reaction was performed as a double-blind study, in a final volume of 25 μL, which contained 5 μL of DNA, 10 μL of Brilliant multiplex QPCR Master Mix (Agilent Technologies), 200 nM forward primer, Plasmo1 (5′-GTTAAGGGAGTGAAGACGATCAGA-3′), and 200 nM reverse primer, Plasmo 2 (5′-AACCCAAAGACTTTGATTTCTCATAA-3′). The TaqMan probe, Plasprobe: 5′-FAM-ACCGTCGTAA TCTTAACCATAAACTATGCCGACTAG-TAMRA-3′ and Falcprobe: 5′-FAM-AGCAATCTAA AAGTCACCTC GAAAGATGACT-TAMRA-3′ were used. The real-time PCR was performed in an ABI 7500 fast real-time PCR instrument (Applied Biosystems) with the following thermal profile: 95 °C for 10 min, and 45 cycles of 95 °C for 15 s and 60 °C for 1 min. The sample was considered positive by identifying the threshold cycle number (Ct) at which normalized reporter dye emission raised above background noise. If the fluorescent signal did not increase within 40 cycles (Ct 40), the sample was considered negative.

The PCR was run on double-blinded samples by a different technician than the one who had performed the DNA extraction. The results were recorded by a third person and aligned with the blinded samples. Ten water samples were added at random in the plate and were all negative. Two positive samples showed a Ct value between 39 and 40. These samples were retested (reextracted), and the final Ct was found to be 26 and 38. Individual results are available in Dataset S1.

Statistics and Analysis (Including PCR).

As stated, the intensity of the test and control lines was analyzed and measured by using ImageJ ( 50). The intensity of the control line (in the red channel) was divided by the intensity of the test line for each strip to obtain the percentage intensity of the control line for each test ( 51).

Confidence intervals for sensitivity data ( Tables 1 and 2) were calculated on the basis of the binomial distribution using the STATA 14.1 statistical package (StataCorp LP).

Data and Materials Availability.

All data are available open access in the University of Glasgow repository ( 53).

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Paper-based microfluidics for DNA diagnostics of malaria in low resource underserved rural communities

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Populations living in remote rural communities would benefit from rapid, highly sensitive molecular, DNA-based diagnostics to inform the correct and timely treatment of infectious diseases. Such information is also becoming increasingly relevant in global efforts for disease elimination, where the testing of asymptomatic patients is now seen as being important for the identification of disease reservoirs.

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The most important reason to communicate with stakeholders early and often is the fact that at the end of the day, they will be the ones who will be tasked with buying and using your device. The greatest product in the world won't be able to help anyone if it never gets put into use. An example of this was shown in lecture with the glucose monitoring watch, where people were worried about how their medical data would be used and relayed to others outside of their control, so they would not use the device.

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Some pros of rapid diagnostic tests include their speed (usually very fast), low cost, multiple parameter testing and ease of use. Some cons of rapid diagnostic tests include lower specificity and sensitivity, possible training to interpret results and ambiguous results (in some cases).

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Dr. Locke's research is focused on optical biosensing for point of care diagnostic purposes. Her research looks towards ways of applying this technology towards monitoring diabetes, cardiac diseases, and gastrointestinal issues.

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Pros: rapid turnaround, low cost, can test for multiple things at once, and convenience
Cons: Lower sensitivity, lower specificity, possible misinterpretation of results, possible incorrect usage of the tests

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There is a device to diagnose childhood pneumonia in low resource settings using automatic segmentation of respiratory sounds. The auscultation device uses various statistical methods and models such as a Mel-based filter bank, Gaussian mixture model, and different vectors and probability matrices. I find this aspect the most interesting given I have worked on a similar device idea and used various matrix and filter techniques. https://ieeexplore.ieee.org/abstract/document/7590695https://ieeexplore.ieee.org/abstract/document/7590695

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Towards an unsupervised device for the diagnosis of childhood pneumonia in low resource settings: Automatic segmentation of respiratory sounds

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Pneumonia remains the worldwide leading cause of children mortality under the age of five, with every year 1.4 million deaths. Unfortunately, in low resource settings, very limited diagnostic support aids are provided to point-of-care practitioners.

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The perspectives of all stakeholders are important because they altogether determine the success of the device. For example, if clinicians support a device, but the investors do not, then the device may not be marketed. Additionally, if investors support a certain device, but the safety regulators do not, the device may not receive clearance by the FDA or the appropriate regulatory group for the country.

# data[].attributes.body
Dr. Locke's research focuses on optical biosensing for point-of-care monitoring and diagnosis. This may be applied to devices to diagnose or monitor diabetes, digestive system disorders such as IBS, oral cancers, or cardiac disease.

# data[].attributes.body
Some pros of rapid diagnostic tests usually include lower costs, less wait time for the patient as well as more convenience because they do not have to worry about traveling or communicating later on about their test results. Some cons would be the efficacy of the tests, hesitancy from medical professionals, and the medical knowledge needed to interpret the results properly.

# data[].attributes.body
Pros of rapid diagnostic tests include quick turnaround time for results, relatively low cost, and ability to be used for testing of multiple parameters. Some cons include low sensitivity, required training, and qualitative results for some tests.