Performance verification of detecting COVID-19 specific antibody by using four chemiluminescence immunoassay systems

BackgroundThe purpose of current study is to evaluate the analytical performance of seven kits for detecting IgM/IgG antibody of corona virus (2019-nCoV) by using four chemiluminescence immunoassay systems. Methods50 patients diagnosed with 2019-nCoV infection and 130 controls without corona virus infection from the General Hospital of Chongqing were enrolled in current retrospective study. Four chemiluminescence immunoassay systems including seven IgM/IgG antibody detection Kits for 2019-nCoV (A_IgM, A_IgG, B_IgM, B_IgG, C_IgM, C_IgG, D_Ab) were employed to detecting antibody concentration. Chi-square test, receiver operating characteristic (ROC) curve and Youdens index were demonstrated to verify the cutoff value of each detection system. ResultsThe repeatability verification results of the A, B, C, and D system are all qualified. D-Ab performances best (92% sensitivity and 99.23% specificity), and B_IgM worse than other systems. Except for the system of A_IgM and C_IgG, the optimal diagnostic thresholds and cutoff value of other kits from recommendations are inconsistent with each other. B_IgM got the worst AUC and C_IgG had the best diagnostic accuracy. More importantly, B_IgG system have the highest false positive rate for testing patients with AIDS, tumor and pregnant. A_IgM system test showed highest false positive rates among elder over 90 years old. ConclusionsSystems for CoVID-2019 IgM/IgG antibody test performance difference. Serum diagnosis kit of D-Ab is the most reliable detecting system for 2019-nCoV antibody, which can be used as an alternative method for nucleic acid testing.

Investigation on the trueness and precision of routine clinical biochemistry tests in the third-grade class-A hospitals of Chongqing City / 临床检验杂志

Objective@#To investigate the trueness and precision of routine clinical biochemistry tests in the third-grade class-A hospitals of Chongqing city. @*Methods@#The fresh frozen serum samples were assigned the target values with reference methods, and then allocated to the clinical laboratories of the third-grade class-A hospitals in Chongqing city for testing. The trueness and precision were analyzed and evaluated. @*Results@#The pass rates of trueness of creatinine (Cr), total protein (TP), total bilirubin (T-Bil), uric acid (UA) and glucose (Glu) in 33 clinical laboratories were below 50%. The pass rate of trueness of UA (33%) in the closed detection system was lower than that in the opening detection system (79%, P=0.033). In the opening detection system, the pass rate of trueness of Cr in the mode with the same brand of reagents and calibration materials was higher than that with different brands (P=0.014). The precisions of level 1 of T-Bil and Urea in the closed detection system were better than that in the opening detection system (P=0.043 for T-Bil; P=0.031 for Urea). @*Conclusion@#The trueness of clinical biochemistry tests in the third-grade class-A hospitals of Chongqing city needs to be further improved. There is no significant difference in trueness and precision between the opening detection system and the closed detection system, even the performance of some tests in the opening detection system is better than that in the closed detection system.