Enhanced monitoring and detection of recent genotype 3 hepatitis E virus infection through urine antigen testing

Hepatitis E virus (HEV) is the leading cause of acute viral hepatitis. Numerous studies have investigated the dynamics of HEV infection markers, but the most suitable marker for diagnosing ongoing or recent HEV infection remains to be determined. Recent evidence suggests that serum antigen testing is superior to serum IgM and RNA quantification. Moreover, it has been found that infected individuals excrete HEV antigen in significant quantities through urine. To address this question, we conducted a longitudinal analysis involving 16 patients with acute or chronic HEV infection in an area where genotype 3 HEV is prevalent. Our findings indicate that the diagnostic and monitoring capabilities of antigen testing for HEV infection can be further enhanced by measuring it in urine. Additionally, we were able to demonstrate that this enhancement is likely due to the presence of HEV-reactive IgG in blood plasma, which hampers efficient detection of HEV antigen through sandwich ELISA. In conclusion, urine-based antigen testing appears to be superior to measuring anti-HEV antibodies or viral RNA for diagnosing suspected HEV infection and monitoring ongoing infections.