PERFORMANCE OF HEPATITIS-C VIRUS (HCV) ANTIBODY-TEST SYSTEMS IN RELATION TO HCV-RNA DETECTION IN THE DIAGNOSIS OF HCV INFECTION

Background: Hepatitis C virus antibody (anti-HCV) test systems for scr eening and conformation of blood donations have proved their value. Th e systems were later adopted for diagnosing patients suspected of hepa titis C. Objectives: 1) to study the clinical value of the recombinant immunoblot assay (RIBA) in routine diagnostics of patients suspected of HCV infection using HCV-PCR as the most definitive test and 2) to c ompare the performance of RIBA-2 with RIBA-3. Materials: From May 1991 to August 1996 more than 4300 patients were tested for anti-HCV. All anti-HCV (EIA) positive patients were tested with RIBA-2 or RIBA-3 and HCV-PCR. Results: We found no difference in the overall performance o f RIBA-2 compared to RIBA-3. There was a tendency to fewer indetermina te results using RIBA-3 compared to RIBA-2 (5% vs. 9%), but this was n ot statistically significant. The NS5 band in RIBA-3 did not improve s ensitivity or predictive value. Of RIBA-2 and RIBA-3 positive patients , 71% and 66% respectively were found to be HCV-RNA positive. Two samp les that were negative using RIBA were HCV-RNA positive. Conclusion: R IBA testing in anti-HCV (EIA) positive patients added no clinically us eful information to the screening results. We have therefore changed t he diagnostic strategy so that all anti-HCV (EIA) positive patients ar e tested for HCV-RNA.