ANTI-HEPATITIS-C VIRUS (ANTI-HCV) SEROCONVERSION IN PATIENTS UNDERGOING HEMODIALYSIS - COMPARISON OF 2ND-GENERATION AND 3RD-GENERATION ANTI-HCV ASSAYS

Background: The results obtained in sequential specimens from recently infected subjects generally provide the best means of comparing the sensitivity of assays. Study Design and Methods: The sensitivity of second- and third-generation assays for antibody to hepatitis C virus (HCV) was compared on sequential specimens, generally collected at monthly intervals from 45 patients undergoing hemodialysis who seroconverted for HCV between 1980 and 1990. Results: Fifteen patients (33%) were positive earlier in the third-generation enzyme-linked immunosorbent assay (ELISA) with a mean difference of 17 days (range, 7-30) between the last negative and the first positive specimens. At the first rise in alanine aminotransferase, and at its peak, 63 and 91 percent of the patients, respectively, were anti-HCV positive in the third-generation ELISA. Third-generation recombinant immunoblot assay (RIBA) reacted at the same time as third-generation ELISA, Of the first specimens that were positive in second-generation ELISA, 44 percent reacted and 56 percent were indeterminate in third:generation RIBA, while 10 percent reacted, 72 percent were indeterminate, and 18 percent did not react in second-generation RIBA. From the beginning to the end of the follow-up, antibody to c33c was the most prevalent, followed in descending order by antibody to c22-3, antibody to c100-3, and antibody to NS5: 56, 54, 26, and 18 percent, respectively, at time 0, and 100, 86, 83, and 31 percent, respectively, 12 months later. Conclusion: Third-generation assays (both ELISA and RIBA) were more sensitive than second-generation assays in the diagnosis of HCV infection, in that positive results were obtained earlier and a higher proportion of specimens were confirmed positive in RIBA testing.