The Utilization of Anti-HCV Signal to Cut-off Ratio (S/CO) in Predicting HCV-Viremia

Abstract

Hepatitis C virus (HCV) infection is a common cause of acute and chronic hepatitis among Thais population. The routine reactive anti-HCV is not indicated to active HCV infection. HCV antigen is not available in the routine service.   An expensive RT-PCR study is required to confirm HCV viremia. The aim of the current study was to determine the relation of signal-to-cut  off (S/CO) ratio of anti-HCV antibody in predicting HCV viremia.  A cross-sectional study of 641 anti-HCV antibody positive  patients by Architect  anti-HCV  3.0  attending at King Chulalongkorn  Memorial Hospital. All samples were also tested for HCV-RNA by Cobas Tagman HCV testing. Among the 641 patients with HCV infection, 385 (60.06%) were male and 256 (39.94%) were female with the mean age of

51.97  ± 12.09  years, ranging 15-87  years. There was significant difference in S/CO ratio of 5.04 between viremic and non-viremic patients. The sensitivity and specificity were 100% and 68.12%, respectively, whereas the positive and negative predictive values were 87% and 100%, respectively. The study showed that anti-HCV S/CO ratio is useful to predict non-viremic  patients. A cut-off  value of  5.04  by Architect anti-HCV 3.0  can determine the utility of  HCV-RNA  testing. Patients with S/CO < 5.04 might not be viremic; therefore, HCV-RNA testing is not recommended.