ABSTRACT
To evaluate the frequency of the false positive results, we examined 168 patients for the presence of HCV using two HCV antibody assay systems, Synpep HCV-EIA (Synpep) and Abbott EIA II (Abbott). The results obtained by the two methods were significantly different in 22 patients. Cases in 17 of these patients, the results were positive with Abbott but negative with Synpep, and there were no clinical signs or delectable virus RNA. However, in 2 cases, the results were markedly positive with Abbott and weakly positive with Synpep. The presence of virus RNA and the increase of transaminase were observed in one case but both were noted in the other case. The serum of these two patients reacted with the C33C and C22-3 regions in RIBA II. We observed another 2 cases in which the elevation of the cut-off index with Synpep preceded that with Abbott at the early stage of acute hepatitis C. We also compared the cut-off index with the histology activity index (HAI) score determined by liver biopsy. The average cut-off index with Synpep was proportional to the HAI score in the range between 0 and 13. Based on the cut-off index/HAI score relationship, we suggest that patients with inactive chronic hepatitis show a Synpep cut-off index less than 11.
