Evaluation of Architect anti-HCV Signal to Cutoff Ratios for Predicting Hepatitis C Viremia Using COBAS AmpliPrep/COBAS TaqMan HCV Quantitative Test

Abstract

The aim of the study is to evaluate the significance of the Architect anti-HCV signal to cutoff (S/CO) ratios for predicting hepatitis C viremia and determine the optimal S/Co ratio value for Architect anti-HCV assay. The results of patients who underwent HCV RNA quantitative assays because of positive anti-HCV from January 2015 to August 2019 were retrospectively analyzed, including S/Co ratio values, HCV RNA quantitative results, alanine aminotransferase (ALT), and aspartate transaminase (AST) values. Binary logistic regression and Spearman's correlation coefficient were used to analyze the collected data. Receiver-operating characteristics curve (ROC) was applied to analyze the predicting values of the indexes. In total, 811 patients were included in our study and HCV viremia was detected in 342 (42.1%) patients. There is no correlation between anti-HCV S/CO ratio and HCV RNA level. The samples with an S/Co ratio between 1 and 4 (271/271, 100%) were all HCV RNA negative. The area under the ROC curve of anti-HCV S/CO ratio was 0.8714 and the maximal Youden index was 0.681 at an optimal cutoff S/CO ratio value of 8.99. With the cutoff value of 1.0, the Architect anti-HCV assay showed excellent sensitivity but poor specificity in predicting HCV viremia. An S/Co ratio of 8.99 was optimal for further confirmation testing of HCV viremia.