Screening haemodialysis patients for hepatitis C in Vietnam: The inconsistency between common hepatitis C virus serological and virological tests

Summary Selecting the appropriate screening method and interval for the early detection of hepatitis C virus ( HCV ) infection in low‐resourced haemodialysis settings is a challenge. The challenge occurs when patients are classified as HCV ‐ RNA positive but negative to HCV ‐core antigen ( HCV ‐coreAg), anti‐ HCV and genotyping tests. We aim to clarify the inconsistency between HCV ‐ RNA , HCV ‐coreAg, anti‐ HCV and HCV genotyping tests in haemodialysis patients and determine the reliability of HCV ‐coreAg as a routine two‐monthly screening strategy. Haemodialysis patients were tested every 2 months between 2012 and 2014 at the largest district haemodialysis unit in Ho Chi Minh City, Vietnam, for aminotransferases, anti‐ HCV antibodies, HCV ‐coreAg, HCV ‐ RNA and HCV genotype. HCV ‐coreAg and anti‐ HCV results were tested against HCV ‐ RNA for sensitivity, specificity, positive predictive value ( PPV ), negative predictive value ( NPV ). All 201 patients participated in the study. The HCV ‐coreAg test performed better than the anti‐ HCV test for sensitivity (100% vs 31%), NPV (100% vs 90%) and accuracy (100% vs 90%). The HCV ‐coreAg and anti‐ HCV tests performed no differently for specificity (100% and 98%, respectively) or PPV (100% and 73%, respectively). Kappa values for HCV ‐coreAg and anti‐ HCV tests were 1 and 0.39, respectively. Early detection of HCV for the purpose of infection prevention requires a high level of sensitivity and HCV ‐coreAg performed better in our chronic haemodialysis population as a two‐monthly screening method than routine anti‐ HCV testing. HCV ‐coreAg test is less labour‐intensive with a higher level of accuracy in patients with low viral loads making it cost effective for low‐resourced settings. Repeating genotyping may be required in HCV ‐coreAg positive patients with a low viral load.