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 screening and confirmation of blood donations have proved their value. The systems were later adopted for diagnosing patients suspected of hepatitis 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 compare 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 of RIBA-2 compared to RIBA-3. There was a tendency to fewer indeterminate results using RIBA-3 compared to RIBA-2 (5% vs. 9%), but this was not statistically significant. The NS5 band in RIBA-3 did not improve sensitivity or predictive value. Of RIBA-2 and RIBA-3 positive patients, 71% and 66% respectively were found to be HCV-RNA positive. Two samples that were negative using RIBA were HCV-RNA positive.

CONCLUSION

RIBA testing in anti-HCV (EIA) positive patients added no clinically useful information to the screening results. We have therefore changed the diagnostic strategy so that all anti-HCV (EIA) positive patients are tested for HCV-RNA.