PMO-164 HCV p22 antigen test: serological response and diagnostic advantages

Introduction The p22 ELISA stains for part of the nucleocapside of hepatitis C virus (HCV) and has recently become commercially available. The current British Society of Gastroenterology guidelines recommend ELISA towards antibodies against HCV Ab. Only 27% of patients with acute HCV are able to clear the virus, 1 however, early treatment in the acute phase is known to improve outcomes and rates of Sustained Virological Response. 2 This has been advocated in certain subgroups (patients co-infected with HIV or moderate-severe liver disease). This case demonstrates the serological response during an acute hepatitis infection with regards to ALT, HCV Ab, HCV RNA and the new p22 HCV antigen test. Methods Sequential blood samples were obtained from a patient with end stage renal failure who developed acute HCV infection while on haemodialysis. Liver function tests, ELISA to antibody to HCV, HCV RNA PCR and antigens to p22 were performed retrospectively. Results The p22 ELISA result became positive at an earlier time point before a rise in ALT or the ELISA HCV antibody result. Conclusion The p22 ELISA is a robust and reliable test that allows for earlier detection of HCV viraemia. This would be of crucial importance in patient subgroups that need early treatment in the acute phase or in populations where early detection would be required to reduce risk of cross-transmission (eg, haemodialysis units). This test offers several advantages over PCR, which though sensitive, involves complex methodology that makes it unsuitable for diagnostic laboratories. Further investigation would be required to establish the role of treating during the hyper-acute phase, in patients with negative HCV antibody and normal ALT. Competing interests None declared. References 1. Micallef JM , Kaldor JM, Dore GJ. Spontaneous viral clearance following acute hepatitis C infection: a systematic review of longitudinal studies. J Viral Hepat 2006; 13 :34–41. 2. Corey KE , Mendez-Navarro J, Gorospe EC, et al. Early treatment improves outcomes in acute hepatitis C virus infection: a meta-analysis. J Viral Hepat 2010; 17 :201–7.