Investigation of sera reactive to hepatitis C virus by second-generation enzyme immunoassay

Hepatitis C virus antibodies were detected by a second-generation enzyme immunoassay and investigated with a second-generation recombinant immunoblot assay. Most sera with optical density values of > or = 2.0, particularly those with optical densities of > or = 2.0 after a further 10-fold dilution, were positive in the second-generation recombinant immunoblot assay. Repeat testing of hemodialysis patients revealed excellent reproducibility and increased sensitivity of the second-generation enzyme immunoassay.