RESUMO
Objective To evaluate the usefulness of anti -HCV signal-to-cutoff (S/CO)ratio, AST, ALT and the combined examination of anti-HCV S/CO, AST, ALT for predicting HCV RNA results by a model of logistic regression and receiver -operating characteristic (ROC) curve.Methods Five hundred and eighty -eight anti-HCV positive samples were tested by ELISA , followed by RT-PCR to detect HCV-RNA and enzyme rate method to detect AST, ALT.Patients were divided into viremia and non -viremia groups according to HCV-RNA results.Logistic regression and ROC curve analysis was performed to evaluate the diagnostic accuracy of each index for a diagnosis of viremia.Results The serum anti-HCV S/CO ratio, AST, ALT of HCV-RNA positive group were higher than HCV-RNA negative group, showing significant statistical difference ( P AST >ALT.The Area Under Curve(AUC) of the combined examina-tion of anti-HCV S/CO ratio, AST and ALT was 0.949(95% confidence interval,0.932 to 0.966), higher than the AUC of anti-HCV S/CO ratio, AST and ALT single index examinations , which was 0.894(95 % confidence interval, 0.862 to 0.926), 0.823(95%confidence interval, 0.789 to 0.856) and 0.788(95% confidence interval, 0.750 to0.826 ) respectively.C onclusions The diag-nostic relevance of the three biochemical markers for predicting the presence of viremia was anti -HCV S/CO ratio >AST >ALT.The combined examination of anti-HCV S /CO ratio, AST and ALT in predicting hepatitis C viremia is superior to any single index examina -tion and it can increase the detecting ability of HCV -RNA greatly.