应用ROC曲线分析颗粒凝集法检测儿童肺炎支原体抗体在近期感染中的效价水平

目的探讨分析颗粒凝集法(PA)检测儿童肺炎支原体抗体在近期感染中的最优诊断界值。方法对260例以干咳和发热为主要症状的疑似肺炎支原体感染患儿,经荧光定量聚合酶链反应(PCR)法确诊肺炎支原体感染160例及非肺炎支原体感染100例,采用颗粒凝集法(PA)检测疑似患儿血清中的肺炎支原体抗体水平,利用受试者工作特征曲线(ROC曲线)判断抗体效价的最优截断值。结果抗体效价水平>1∶160为最佳的阳性截断值,即在判断近期感染时的最优临床诊断界值。此时的灵敏度为67.5%,特异性为95%,阳性预测值95.6%,阴性预测值64.6%,ROC曲线面积为0.868。结论 PA法检测肺炎支原体抗体对儿童肺炎支原体感染具有一定的诊断价值,其抗体水平能反映患儿的近期感染或既往感染。

Application of ROC curve analysis in the detection of antibody against Mycoplasma pneumonia in particle agglutination test in recent infected children

Objective To determine the optimal cut-off value of particle agglutination test（PA） for the detection of antibody against Mycoplasma pneumoniae（M.pneumoniae） in recently infected children.Methods Two hundred fifty children patients with dry cough and fever as the main symptoms were included in this study.Real-time quantitative PCR indicated that M.pneumoniae infection in 150 patients and non-M.pneumoniae infection in 100 patients.PA was used to examine serum M.pneumoniae specific antibody in these children and ROC curve was made to determine the optimal antibody titer cut-off value.Results The antibody titer 1： 160 was considered as the positive cut-off value for determining recent M.pneumoniae infection.At this point sensitivity,specificity,positive predictive value and negative predictive value were 67.5%,95%,95.6%,and 64.6%,respectively.ROC curve area was 0.868.Conclusion The PA test for M.pneumoniae antibody detection has certain diagnostic value for M.pneumoniae infection in children and the antibody level may differentiate recent infection from past infection.