Evaluation of biochemical, hematological, RIBA and PCR assays in predicting viremia in anti-HCV positive patients

Introduction: The detection of HCV-RNA by PCR assays is considered to be the gold standard for confirming the presence of HCV viremia. However, high costs, long and laborious procedures limit their widespread usage. This retrospective study was conducted to assess the predictive performances of biochemical and hematological parameters, anti-HCV signal-to-cutoff (S/CO) ratios and RIBA assay for HCV viremia. Methodology: Medical records of 210 patients with positive anti-HCV results were analyzed. Samples were tested for anti-HCV by the Roche Elecsys assay. RIBA and PCR assays were performed with Inno-Lia HCV Score test, and Roche Cobas TaqMan HCV test, respectively. Results: Anti-HCV positive patients were categorized into two groups: positive HCV-RNA(viremic) group (n = 94) and negative HCV-RNA(non-viremic) group (n = 116). All viremic patients had positive RIBA results, while in the non-viremic group, 80 (69%) patients had negative/indeterminate RIBA results and 36 (31%) patients had positive RIBA results. Compared with the non-viremic group, the viremic group had significantly higher alanine aminotransaminase (ALT), aspartate aminotransferase, gamma-glutamyl transferase, mean platelet volume, platelet distribution width and anti-HCV levels, and significantly lower platelet count and plateletcrit levels (p < 0.05). With multivariate logistic regression analysis, serum ALT and anti-HCV levels were found to be strong predictive factors for HCV viremia. A S/CO ratio of ≥ 12.34 was identified as the optimal anti-HCV level to predict viremia. Conclusions: An anti-HCV S/CO ratio of 12.34 can determine the necessity for PCR assay, when carefully evaluated together with the biochemical and hematological evidence. This approach may reduce the cost of diagnosis particularly in low-resource settings.