Diagnosis of hepatitis C virus infection using two second-generation enzyme immunoassays with a recombinant immunoblot assay for confirmation.

A total of 1,016 serum samples from patients with either non-A, non-B hepatitis or risk factors for hepatitis C virus (HCV) infection were examined in two second-generation enzyme immunoassays (EIAs), the UBI HCV EIA (Organon Teknika, The Netherlands) and the Wellcozyme anti-HCV (Murex Diagnostics, UK), for detection of antibodies to HCV. An immunoblot assay that uses four recombinant antigens, the 4-RIBA (Chiron, USA), was used as a confirmatory assay. Of the 1,016 samples, 195 (19.2%) were reactive in both EIAs, while ten yielded discrepant results. One hundred eighty of the 195 (92%) positive reactions were confirmed in the 4-RIBA; 13 sera yielded an indeterminate result and two were negative. None of the sera with discrepant results reacted positively in the confirmatory test, while two sera showed an indeterminate pattern. In contrast to the screening of antibodies to HCV among blood donors, confirmatory testing of antibodies to HCV with the 4-RIBA seems to have limited added value in the diagnostic examination of clinical samples from patients with suspected HCV infection.