Abstract: Objective To confirm and analyze the cut-off value in anti-hepatitis C virus (HCV) antibody determined by 2 different kinds of enzyme-linked immunosorbent assay (ELISA) analysis systems with receiver operating characteristic (ROC) curve. Methods A total of 202 sera confirmed by recombinant immunoblot assay (RIBA) were determined by domestic addcare ELISA 1100 automatic analysis system and imported combined TECAN with FAME ELISA analysis system for anti-HCV antibody. ROC curve was drawn with absorbance (A) by SPSS 17.0 software, and the optimal cut-off value was obtained. Results According to the results of ROC curve, RIBA as the golden standard, the optimal cut-off values were 0.448 in addcare ELISA 1100 automatic analysis system and 0.406 in TECAN+FAME combined ELISA analysis system. Their sensitivities, specificities, Youden indices and areas under ROC curve were 99.3%, 99.3%; 96.7%, 96.7%; 0.960, 0.960 and 0.998, 0.998. Conclusions The cut-off values are 0.448 and 0.406 in the 2 analysis systems with by ROC curve, and the ambiguous regions are 0.140-0.448 and 0.140-0.406.The 2 ELISA analysis systems can optimize the performance of detection.

Key words: Anti-hepatitis C virus antibody, Enzyme-linked immunosorbent assay, Recombinant immunoblot assay, Cut-off value, Receiver opearting characteristic curve