Detection of HCV core antigen and its diagnostic significance 

Objective To compare the abilities of the hepatitis C virus (HCV) core antigen (cAg) test and the HCV RNA assay for confirming anti-HCV presence in order to determine the clinical utility of the HCV-cAg as an alternative or confirmatory diagnostic tool.Methods Serum samples collected from 158 patients diagnosed with HCV infection were subjected to the enzyme-linked immunosorbent assay-based HCV-cAg test.The optical density (OD) measured values were used to calculate the ratio of specimen absorbance to the cutoff value (S/CO) .Simultaneously, the serum samples were subjected to PCR-based nucleic acid amplification quantitative fluorescence detection of HCV RNA.Results None of the serum samples had a S/CO value<1 for="" the="" hcv-cag="" test="" but="" all="" of="" samples="" had="" a="" co="" value="">5 (100% positive) .The HCV-cAg test sensitivity was 87.05%, specificity was 76.67%, positive predictive value was 96.53%, and negative predictive value was 44.23%.As the S/CO value gradually increased, the significantly higher positive coincident rate of the HCV RNA test decreased.The HCV RNA negative coincident rate was significantly higher than that of the HCV-cAg test.HCV-cAg S/CO values between 1 and 2 corresponded to an HCV RNA values between 1.0×103 copies/ml and 1.0×104 copies/ml.The highest S/CO value obtained was 1.992.Conclusion The HCV-cAg test is comparable to the HCV RNA assay for diagnosing HCV infection.