The Usefulness of Anti-HCV Signal to Cut-off Ratio in Predicting Viremia in Anti-HCV in Patients With Hepatitis C Virus Infection

BACKGROUND: Hepatitis C Virus (HCV) infection is diagnosed by antibody and RNA based methods. Patients with anti-HCV sample rate/cutoff rate (S/CO) ratios > 1 are reported as anti-HCV positive. RNA based methods are introduced to confirm positivity in seropositive samples. OBJECTIVES: The current study aimed to assess relationship between S/CO rates and HCV-RNA levels in the laboratory to identify HCV viremia in patients with a positive anti-HCV. PATIENTS AND METHODS: All serum samples were assayed for anti-HCV by ELISA method. A total of 265 anti-HCV positive patients were tested for HCV-RNA testing by quantitative method using Artus HCV RG Real-time Polymerase Chain Reaction (RT- PCR) kit. Statistical analysis was done by SPSS version 16. RESULTS: Of the 265 patients with HCV infection, 204 (77%) were male and the mean age was 43.53 ± 13.17 years, ranging 1 - 81 years. No correlation was found between S/CO ratios and HCV-RNA levels. There was significant difference in S/CO ratio between viremic and non-viremic subjects. The sensitivity, specificity, negative predictive value, and positive predictive value were 100%, 81.4%, 100%, and 77.2%, respectively in the S/CO ratio of 2.7. CONCLUSIONS: The present study indicated that anti-HCV S/Co ratio is useful to predict non-viremic patients. A cut-off value of 2.7 can determine the usefulness of HCV-RNA testing. Patients with S/CO < 2.7 are not viremic; therefore, HCV-RNA testing is not recommended. It is suggested that laboratories report S/CO ratio along with anti-HCV results to manage HCV infection better, especially in countries that quantitative HCV testing is expensive or not available.