AIM--To evaluate the performance of three newly introduced enzyme immunoassays (EIAs) for hepatitis C virus (HCV) antibodies, based on synthetic oligopeptides as antigens. METHODS--Referred serum samples (n = 173) from people representing groups at high risk of HCV infection were studied. An EIA based on second generation recombinant polypeptide antigens was used for comparison. EIA reactivities were validated by testing repeatedly reactive samples in two recombinant antigen based immunoblot assays. RESULTS--In samples from patients with liver dysfunction and those with bleeding disorders sensitivity of the three peptide based EIAs, manufactured by Innogenetics NV, Biokit SA, and United Biomedical Inc., were all 93%; specificity and efficiency were all greater than 95%. In samples from blood donors (previously tested as positive by the Ortho and Abbott Second Generation EIA) specificity, sensitivity, and efficiency were 95% or greater in all three peptide assays. Sensitivity, specificity, and efficiency of the recombinant antigen based Ortho Second Generation EIA were 100%, 89%, and 93%, respectively, in sera of patients with liver disease and those with bleeding disorders; and 100%, 43%, and 83%, respectively, in prescreened samples from blood donors. CONCLUSION--The peptide EIAs are more specific but less sensitive than the Ortho EIA. Peptide based EIAs should be useful in validating the specificity of Ortho EIA reactivities.