Performance Evaluation Of Different ELISA Analysis System In The Detection Of Hepatitis C Antibody

Objective:To evaluate the performance and conformity of domestic addcare ELISA 1100 full autokinetic ELISA analysis system (addcare ELISA 1100) and imported combine TECAN with FAME ELISA analysis system (TECAN+FAME) in the detection of hepatitis C antibody by same reagent. To confirm and analyze the best diagnostic threshold (S/CO ratio) in hepatitis C antibody test by two different kinds of ELISA analysis system with receiver operating characteristic (ROC) curve. Methods:According to the Clinical and Laboratory Standards Institute(CLSI) document EP12-A2 User Protocol for Evaluation of Qualitative Test Performance; Approved Guideline and China National Accreditation Service for Conformity Assessment(CNAS) document Guidance on the Application of Medical Laboratory Quality and Competence Accreditation Criteria in the Field of Clinical Immunology, the performance of addcare ELISA 1100 and TECAN +FAME were evaluated, include sensitivity, specificity and repeatability, and the analytic performance of two systems were compared. Serum confirmed by recombinant immunoblot assay (RIBA) were tested by indirect ELISA. ROC curve was drawn and S/CO was obtained by SPSS 17.0 software. With RIBA confirmatory test results as the gold standard, Determine the scope of S/CO ratio of the positive predictive higher than 95% of anti-HCV detection of two ELISA analysis system. Results:The sensitivity of addcare ELISA 1100 and TECAN+FAME were 96% and 98%, the specificity were 88% and 96%. The intra variation were 5%,8%,10% for addcare ELISA 1100 and 3%,7%,8% for TECAN+FAME, while the inter variation were 8%,12%,15% and 6%,10%,13%, respectively. The coincident rate was 95% (the 95% confidence interval was 88.83%-97.85%), and the positive coincident rate was 94%, the negative coincident rate was 96%. The Kappa K value was 0.90. According to ROC curve, RIBA as the golden standard, the best S/CO ratio was 3.200 in addcare ELISA 1100 full autokinetic ELISA analysis system and 2.900 in TECAN+FAME combined ELISA analysis system, sensitivity, specificity, Youden index were same in the two system. They were 87.5%, 90.0%,0.775, and area under the curve (AUC) are 0.913 and 0.888. The scope of S/CO ratio of the positive predictive higher than 95% of anti-HCV detection of two ELISA analysis system were S/CO≥2.407å'ŒS/CO≥2.571. The positive rate of samples with +20% from the critical value yielded was 100% and the negative rate with -20% from the critical value yielded was 95%. Conclusions:The domestic addcare ELISA 1100 full autokinetic ELISA analysis system and imported combine TECAN with FAME ELISA analysis system have excellent sensitivity, specificity, repeatability, coincidence rate and conformity. The anti-HCV detected by two ELISA analysis system has their best ratio of S/CO and the anti-HCV ELISA S/CO ratio is correlated with confirmation positive, so ELISA S/CO ratio can be used to predict anti-HCV real positive. Study on confirming the best diagnostic threshold in hepatitis C antibody test by ELISA analysis system and the scope of S/CO ratio of the positive predictive higher than 95% are helpful to improve the result’s reliability and reduce the number of confirmatory test.