ABSTRACT
【Objective】 To track and evaluate the clinical diagnostic efficacy of an enzyme linked immunosorbent assay (ELISA) kit for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). 【Methods】 Total antibody (TAb) specific to SARS-CoV-2 in blood donors were determined using ELISA reagent. TAb positive donors were followed up 1 month after blood donation. SARS-CoV-2 specific IgG, IgM and pseudotype lentivirus based neutralization test (ppNAT) were conducted for TAb positive blood donors and follow-up samples. ppNAT and IgG antibodies simultaneously positive in ppNAT positive samples and its follow-up samples was used as the standard for antibodies validation. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy and Youden index of SARS-CoV-2 TAb ELISA were analyzed. 【Results】 Among 16 016 blood donors from January 31 to April 28, 2020, 61 donors were diagnosed as TAb positive, 6 cases were positive for ppNAT, in which 2 were positive for both ppNAT and IgG; 4 of 46 TAb positive follow-up samples were positive for ppNAT, in which 2 were positive for IgG simultaneously. The sensitivity, specificity, PPV, NPV, accuracy, Youden index, false positive rate and false negative rate of SARS-CoV-2 TAb reagent were 100.00%, 99.60%, 3.28%, 100.00%, 99.60%, 99.60%, 0.40% and 0.00%, respectively. 【Conclusion】 SARS-CoV-2 TAb ELISA has high sensitivity and good clinical diagnostic efficacy, but the false positive rate is relatively high in low-risk blood donors. Therefore, ppNAT, IgG and follow-up results should be fully considered in clinical in order to analyze the positive results and determine the infection status more accurately.