ANALYSIS OF ELISA HEPATITIS-C VIRUS-POSITIVE BLOOD-DONORS POPULATION BY POLYMERASE CHAIN-REACTION AND RECOMBINANT IMMUNOBLOT ASSAY (RIBA) -COMPARISON OF 2ND AND 3RD-GENERATION RIBA

A new RIBA-3 (Chiron-Ortho Diagnostic System) was performed for discri minating uninterpretable results of RIBA-2. Recognition of antibodies to hepatitis C virus by RIBA-2 and RIBA-3 was compared among 95 ELISA- 2 (second generation ELISA) positive blood donors and correlated with alanine-aminotransferase (ALAT) levels and viremia, using polymerase c hain reaction (PCR). These studies led to three important conclusions. First, all ELISA-2-positive, RIBA-2-positive and ALAT-positive sample s were found viremic compared with 73 % of ELISA-2-positive, RIBA-2-po sitive and ALAT-negative samples. Then, the comparison of the differen t RIBAs allowed to conclude that RIBA-3 was more sensitive but less sp ecific than RIBA-2. RIBA-3 was interesting to discriminate undetermine d RIBA-2, owing to an improved specificity of C100-3 antigen. In fact, most of the C100-3 positive, RIBA-2 undetermined samples became RIBA- 3 negative whereas C22-3 positive, RIBA-2 undetermined samples became RIBA-3 positive or undetermined. Finally, a significant correlation wa s found between the presence of antibodies against C33-c antigen and v iremia.