Background: Hepatitis C virus (HCV) is the predominant cause of nonA-nonB and post transfusion hepatitis. This study was conducted to evaluate the efficacy of third generation Recombinant Immunoblot Assay (RIBA-3) especially structural and non-structural bands compared with Reverse Transcripatase Polymerase Chain Reactions (RT-PCR) for the diagnosis of hepatitis C infection.

Materials and Methods: Sera of 80 patients with ELIAS-3 positive were analyzed by RIBA-3 and RT-PCR.

Results: Forty-eight out of 80 patients were positive in RIBA-3. Of them 92% was RT-PCR positive and only 4 patients were RN negative. Among 20 samples with 4 bands, 18 (90%) were RNA positive. Among the 18, 3-bands positive, 16(88%) were RNA positive, whereas all of 11(100%) of RIBA-3 positive with anti-capsid and anti-NS3 reactivity are RNA positive. Among the RIBA-3 indeterminate cases (13 patients), HCV-RNA was positive only in 31 % (4 patients). Sera of these four patients were reactive with the core (C22) region in RIBA-3. All samples reacted to NS-4 regions were RT-PCR negative. So samples with indeterminate results in RIBA-3 should be evaluated by RT-PCR for HCV RNA. All samples without any reaction in RIBA-3 were RT-PCR negative.

Conclusion: There were not absolute correlations between the results of RIBA-3 and PCR but all of RIBA-3 positvie with anti-capsid and anti-NS3 reactivity were PCR positive, but other profiles were associated with HCV viremia in about 88%-90% of cases.