目的 在肺结核密切接触者中,以γ-干扰素释放试验(IGRA)为标准,评估使用重组结核杆菌融合蛋白(EC)和结核菌素纯蛋白衍生物(PPD)两种试剂进行皮试的筛查效能及经济效益,为后续学校肺结核筛查工作提供参考依据。方法 将某次肺结核患者的密接人群随机分为EC组和PPD组,以IGRA为标准判断EC或PPD的筛查结果,3个月后完成二次筛查,PPD、EC以及IGRA结果阴性者再次重复该检测。计算两次筛查后EC、PPD试验的灵敏度、特异度、正确指数、Kappa值、预测值和ROC曲线下面积,并分析两者的成本-效果比,使用SPSS 25.0进行统计分析。结果 共筛查肺结核密切接触者491人,脱落9人,EC组239人,PPD组243人。两次筛查后EC组潜伏感染率为4.60%,灵敏度为66.67%,特异度为98.68%,正确指数为97.07%,阳性预测值为72.72%,阴性预测值为98.25%,Kappa值为0.680,ROC曲线下面积为 0.827;PPD组的潜伏感染率为18.93%,灵敏度为69.23%,特异度为83.91%,正确指数为83.13%,阳性预测值为19.57%,阴性预测值97.97%,Kappa值为0.242,ROC曲线下面积为 0.766。EC组每百人的筛查费用较PPD组少,使用成本-效果比(效果为潜伏性结核感染)评估时,EC组高于PPD组;使用皮试和IGRA均阳性的人数作为效果评估时,EC组低于PPD组。仅以皮试结果观察,EC组需要预防性治疗人数为11人(占4.60%) ,PPD组为27人(占11.11%)。结论 在筛查肺结核密接者潜伏性感染时,相较于PPD,EC特异度高,与IGRA检测结果一致性较好。同时,EC可以减少因PPD假阳性而增加的预防性治疗的人数,虽在经济效益方面仍存在争议,但不失为一种较好的皮试方法,具有一定的推广价值。

Objective The screening efficacy and economic benefits of using recombinant mycobacterium tuberculosis fusion protein (EC) or purified protein derivative of tuberculin (PPD) as skin tests were evaluated in close contacts with pulmonary tuberculosis using interferon-gamma release assays (IGRA),providing a reference for subsequent school tuberculosis screening work. Methods The close contacts of tuberculosis patients at a given time was randomly divided into EC group and PPD groups.IGRA was applied as the standard to determine the screening results of EC and PPD.The second screening was completed 3 months later,and the test was repeated again for those with negative PPD,EC,and IGRA results.Calculate the sensitivity,specificity,accuracy index,Kappa value,predictive value,and area under the ROC curve of EC and PPD tests after the two screenings,and analyze their cost-effectiveness ratio.Statistical analyses was conducted using SPSS 25.0. Results A total of 491 close contacts with tuberculosis were screened,9 were shed,239 in the EC group and 243 in the PPD group.After two screening,the latent infection rate of EC group was 4.60%,the sensitivity was 66.67%,the specificity was 98.68%,the correct index was 97.07%,the positive predictive value was 72.72%,the negative predictive value was 98.25%,the Kappa value was 0.680,and the area under the ROC curve was 0.827.The latent infection rate of PPD group was 18.93%,the sensitivity was 69.23%,the specificity was 83.91%,the correct index was 83.13%,the positive predictive value was 19.57%,and the negative predictive value was 97.97%,the Kappa value was 0.242,and the area under the ROC curve was 0.766.The screening cost per hundred people in the EC group was lower than that in the PPD group.When evaluating the cost-effectiveness ratio (effect was latent tuberculosis infection),it was higher in the EC group than that in the PPD group.When evaluating the effect using the number of people who were positive for both skin tests and IGRA,it was lower in the EC group than that in the PPD group.Based solely on the results of the skin test,11 patients (4.60%) in the EC group required preventive treatment,while 27 patients (11.11%) in the PPD group. Conclusion Compared to PPD,EC has higher specificity and better consistency with IGRA detection results in screening for latent infections in close contacts of pulmonary tuberculosis.At the same time,EC can reduce the number of people receiving preventive treatment due to false positive of PPD .Although it is still controversial in terms of economic benefits,it is still a better method of skin test and has some value for dissemination.