Cases of hepatitis A are not clinically distinguishable from other types of acute viral hepatitis. Specific diagnosis is made by the detection of HAV-specific Immunoglobulin G (IgM) antibodies in the blood. Additional tests include reverse transcriptase polymerase chain reaction (RT-PCR) to detect the hepatitis A virus RNA and may require specialized laboratory facilities. 

The hepatitis E virus is transmitted mainly through the fecal-oral route due to fecal contamination of drinking water. This route accounts for a very large proportion of clinical cases with this disease. The risk factors for hepatitis E are related to poor sanitation, allowing virus excreted in the faeces of infected people to reach drinking water supplies.

Other routes of transmission have been identified but appear to account for a much smaller number of clinical cases. These routes of transmission include:
-      ingestion of undercooked meat or meat products derived from infected animals (e.g. pork liver);
-      transfusion of infected blood products; and
-      vertical transmission from a pregnant woman to her baby.

Cases of hepatitis E are not clinically distinguishable from other types of acute viral hepatitis. However, diagnosis can often be strongly suspected in appropriate epidemiologic settings, for example when several cases occur in localities in known disease-endemic areas, or in settings with risk of water contamination, when the disease is more severe in pregnant women, or if hepatitis A has been excluded.
 
Definitive diagnosis of hepatitis E infection is usually based on the detection of specific IgM antibodies to the virus in a person’s blood; this is usually adequate in areas where disease is common. Rapid tests are available for field use.
 
Additional tests include reverse transcriptase polymerase chain reaction (RT-PCR) to detect the hepatitis E virus RNA in blood and/or stool; this assay requires specialized laboratory facilities. This test is particularly needed in areas where hepatitis E is infrequent, and in cases with chronic HEV infection.