Role of HEV antigen detection in HEV-related acute viral hepatitis and acute liver failure.

Detection of HEV antigen presents as an interesting low cost, novel, and rapid diagnostic technique to ascertain HEV viremia where facilities for reverse transcriptase polymerase chain reaction (RT PCR) are sparse. This study was undertaken to assess the relative efficacy of HEV antigen detection by ELISA with currently available diagnostic tests in patients of HEV-related acute viral hepatitis (AVH) and acute liver failure (ALF). This study included 36 ALF and 64 AVH cases. HEV RNA and HEV viral load were determined by RT PCR and real time PCR, respectively. Evidence of recent HEV infection was detected in 45/64 AVH cases and 22/36 ALF cases. IgM anti-HEV antibody, HEV RNA, and HEV antigen were positive in 34/45 (75.56%), 26/45 (57.77%), and 21/45 (46.66%), in the AVH group, and 16/22 (72.72%), 14/22 (63.63%), 12/22 (54.54%) in ALF group, respectively. The concordance between HEV RNA and HEV antigen was 75.56% (P < 0.01) with κ-coefficient of 0.516 and 75.27% (P = 0.07) with κ-coefficient of 0.441 (P = 0.07) in the AVH and ALF patients, respectively, indicating moderate concordance. It was established that HEV antigen detection can be used as a valuable marker of active viremia and a cheaper surrogate to HEV RT PCR, particularly in window period, pregnant and immunocompromised patients, however, it did not correlate with severity of disease or influence the final outcome of illness in any of the study groups. J. Med. Virol 88:2179-2185, 2016.