HEPATITIS-C VIRUS-INFECTION IN VOLUNTEER BLOOD-DONORS IN TAIWAN - EVALUATION BY HEPATITIS-C ANTIBODY-ASSAYS AND THE POLYMERASE CHAIN-REACTION

A total of 2671 plasma samples that were selected from 22 500 volunteer blood donors in Taiwan were studied for hepatitis C virus (HCV) infection. The donors were stratified into three groups by serum alanine aminotransferase (ALT) levels. Of the donors, 20 768 (92.3%) had an ALT level less than 30 IU/L (group 1), 1080 (4.8%) had an ALT level between 31 and 45 IU/L (group 2), and 652 (2.9%) had an ALT level greater than 45 IU/L (group 3). To study anti-C100-3 hepatitis C antibody, 2023 plasma samples (10%) from group 1, 321 (30%) from group 2, and 327 (50%) from group 3 were randomly selected and tested. Twenty-one (1.04%) of group 1 donors, 13 (4.05%) of group 2 donors, and 26 (7.95%) of group 3 donors were positive for anti-C100-3, respectively. These seropositive samples were further tested by a recombinant immunoblot assay, by a polymerase chain reaction for HCV RNA, by a second-generation recombinant antigen-based immunoassay (r-HCV), and by a synthetic peptide-based immunoassay (EIA3) for HCV antibodies. By the polymerase chain reaction, 26 of the 60 donors were positive for HCV RNA. The HCV RNA was more frequently found in donors with an ALT level greater than 45 IU/L than in those with an ALT level less than 45 IU/L (15 of 26 vs nine of 34, respectively); in donors who were recombinant immunoblot assay reactive or indeterminate than in those who were recombinant immunoblot assay negative (17 of 21 or seven of 14 vs two of 25, respectively); and in donors who were EIA3 positive (25 of 33 vs one of 27) or r-HCV positive (25 of 35 vs one of 25). Based on these data, we anticipate that screening by anti-C100-3 in Taiwan will exclude approximately 3280 potentially infectious donations under the current screening policy but will result in the loss of 6860 donations that will be negative for HCV RNA per year. Because of its high sensitivity and specificity, EIA3 or r-HCV seems to be a potentially better screening method for HCV carriers.