Relevance of recombinant immunoblot assay III to HCV-RNA polymerase chain reaction positivity and IGM antibody to HCV core antigen for HCV infection confirmation

ABSTRACT

Currently the second and third generation enzyme immunoassays [EIA2-EIA3] for hepatitis Virus antibody [anti-HCV] are the most practical screening tests for the diagnosis of HCV infection. The need for confirmatory test depends on the clinical setting and the likelihood of a true - positive EIA result. The most appropriate approach is to retest for anti-HCV using recombinant immuno-blot assay [RIBA] and then test for HCV-RNA using PCR assay in those who are RIBA positive or indeterminate. A third generation supplemental test [RIBA III] has been introduced. It appears to be more specific test based on a better correlation with RNA PCR results with a reduced number of indeterminate results. To study the clinical Value of the recombinant immunoblot assay [RIBA] in routine diagnostics of patients with HCV infection using HCV PCR as the most definitive test We further studied the correlation between HCV core IgM positivity and HCV RNA detection by PCR. Patients 47 patients with chronic hepatitis after more than 6 months disease duration. Outcome measures: Liver function tests [ALT, AST, GGT], Hepatitis C virus antibody IgG by Enzyme immunoassay version III; HCV antibody IgM by ELISA technique, HCV antibody using Recombinant Immunobloting Assay [RIBA]; quantitative HCV RNA estimation using amplisensor assay after RNA extraction. high viremia was considered in samples with more than 106 copies/ml and low viremia with samples less than 10[6] copies/ml. Negative reaction was considered when no reaction was obtained. Significantly greater number of patients with HbcIgG+ve/HCV IgM +ve had +ve NS5 b and when compared to those with HBc IgG -ve/HCV IgM+ve. Those with HBc IgG +ve/HCV IgM-ve showed highly significantly fewer number of positive C3+C4 b and cases when compared to the HBcIgG ve/HCV IgM+ve and HbcIgG+ve/HCV IgM +ve patients. Likewise, highly significant fewer number of positive C1+C2 cases with HBc IgG +ve/HCV IgM-ve were obtained when compared to cases with HBcIgG -ve/HCV IgM+ve and HbcIgG+ve/HCV IgM +ve patients. our findings suggest that ELISA-3 was at par with RIBA III and it can be recommended for routine screening for anti-HCV. However, despite the cost, the combination of both ELISA-3 and qualitative or quantitative PCR for HCV RNA allows a definitive classification of HCV diagnosis