ELISA for anti-HCV antibody employing a shorter synthetic core region peptide.

A new ELISA for anti-HCV antibody was developed employing a shorter synthetic N-terminal peptide, 2-62aa, within the core region of 1-191aa. The basic performance of the assay was comparable to three other second-generation assays using longer HCV core antigens. To evaluate assay performance at the borderline level, 25 samples with indeterminate results were selected from 3000 routine serum samples. Only 5 of the 25 sera were found to be HCV-RNA-positive by a nested PCR assay and with apparent clinical evidence of HCV infection. The results of the new ELISA agreed with those of the PCR-RNA test in 23/25 (kappa statistics 0.75), whereas C22-3 of the RIBA II test using 2-120aa of the core agreed in 9/25 (0.09), the Abbott pHCV-34 EIA test using 1-150aa agreed in 10/25 (-0.12), and a neutralization inhibition assay for Abbott EIA II using 2-120aa agreed in 6/25 (0.02). These results indicate that the UBI CORE ELISA has greatly improved specificity and can be a useful indication of viremia in HCV infection.