应用回归方程设置迈瑞CL-6000i化学发光系统检测梅毒螺旋体抗体的灰区范围

Application of regression equation for setting Mindray CL-6000i system in detecting the gray zone of treponema pallidum antibody

目的应用回归方程计算迈瑞CL-6000i化学发光免疫分析(CLIA)系统检测梅毒螺旋体抗体(TP-Ab)的灰区范围。方法选取广元市中心区医院2021年1月至2021年9月通过迈瑞CL-6000i化学发光系统进行TP-Ab检测的患者数据441份,以同期进行的TP-Ab明胶颗粒凝集试验(TPPA)结果为对照进行统计分析。结果441例患者中TP-Ab阳性患者413例[临界值指数(COI)≥1.00],阴性患者28例(COI<1.00)。以TP-Ab化学发光值为自变量,以阳性预测概率为因变量,应用回归分析建立最优拟合模型为三次曲线模型,回归方程为Y=0.001X3-0.026X2+0.289X-0.017,调整后R2=0.983。通过该公式计算当阳性预测概率Y等于0.95时,化学发光COI值为5.474,以此为灰区上限。当COI≤5.474时,以COI≥1.00为阳性,TP-Ab诊断梅毒的敏感度为96.7%,特异度为37.7%,诊断效率为65.4%,假阳性率高达62.3%。结论应用回归方程设置CLIA法(迈瑞CL-6000i)检测TP-Ab的COI值灰区范围为1~5.474,当COI值≤5.474时,敏感度较高,特异度欠佳,假阳性出现的可能性大,建议行TPPA或者其他梅毒螺旋体血清学试验进行辅助判断,避免误诊。

Objective To discuss the gray zone results of the chemiluminescent immunoassay(CLIA)system of Mindray CL-6000i in detecting treponema pallidum antibody(TP-Ab)by using regression equation.Methods From January 2021 to September 2021,a total of 441 patients were selected as subjects who were detected for COI value of TP-Ab by the CLIA method(with Mindray CL-6000i)and treponema pallidum particle agglutination(TPPA)in the clinical laboratory of the Guangyuan Central Hospital,and their clinical data were collected.The results of TPPA were considered as gold standard of syphilis.Results A total of 441 patients were enrolled,including 413 TP-Ab positive patients(COI≥1.00)and 28 TP-Ab negative patients(COI<1.00).With the COI value of TP-Ab as the independent variable and positive prediction probability as the dependent variable,regression analysis was used to establish the best fitting model.The regression equation is Y=0.001X3-0.026X2+0.289X-0.017(adjusted R2=0.983).When the value Y is equal to 0.95,X can be calculated(X=5.474),which can be identified as the upper limit of the gray area.When the COI value is less than or equal to 5.474(COI≥1.00 is considered positive),sensitivity of 96.7%and specificity of 37.7%can be obtained.Meanwhile,the diagnostic efficiency is 65.4%and the false positive rate is quite as high as 62.3%.Conclusion The gray zone of TP-Ab detected by the CLIA system(Mindray CL-6000i)ranges from 1 to 5.474.When the COI value≤5.474,high rate of false positives may result in misdiagnosis.In this case,TPPA test is recommended for further judgment.