Hepatitis C virus infection in hemodialysis patients: comparison of two new hepatitis C antibody assays with a second-generation assay

The performance of two new hepatitis C virus antibody (anti-HCV) assays (a third-generation immunoglobulin (Ig)G recombinant immunoblot assay (RIBA 3.0) and hepatitis C virus core IgM (HCV IgM) in the prediction of hepatitis C viremia in hemodialysis patients was compared with that of a second-generation IgG recombinant immunoblot assay (RIBA 2.0). Forty-three patients on maintenance hemodialysis were studied. Aliquots of sera were tested prospectively for anti-HCV by RIBA 2.0, RIBA 3.0, and HCV IgM and for HCV RNA by polymerase chain reaction. Thirty-eight patients were HCV RNA positive. Among those, 7 (18%) were HCV IgM positive, 22 (58%) were RIBA 2.0 positive, and 29 (76%) were RIBA 3.0 positive. All but one viremic patients detected by HCV IgM were also detected by RIBA 2.0 and RIBA 3.0. All viremic patients detected by RIBA 2.0 were also detected by RIBA 3.0. RIBA 3.0 was more sensitive than RIBA 2.0 and HCV IgM in the detection of viremic patients (P = 0.0156 and < 0.0001, respectively). The positive predictive value for HCV IgM was 100% as compared with 96 and 97% for RIBA 2.0 and RIBA 3.0, respectively. The negative predictive value for RIBA 3.0 was 36% as compared with 24 and 14% for RIBA 2.0 and HCV IgM, respectively. At 6-months follow-up of the eight viremic patients without a detectable IgM or IgG anti-HCV response, all patients remained RIBA 2.0 nonreactive, one became RIBA 3.0 indeterminate, and one became HCV IgM positive. These data suggest that HCV IgM has poor sensitivity in the detection of hepatitis C viremia and RIBA 3.0 improves the sensitivity of IgG anti-HCV assays in the early detection of hepatitis C viremia in hemodialysis patients.