Objective: To compare the screening value of QuantiFERON-TB Gold Plus (QFT-Plus) and QuantiFERON®-TB Gold in tube (QFT-GIT) in the auxiliary diagnosis of pulmonary tuberculosis (TB). Methods: A screening test was performed. Patients who were hospitalized in Guangzhou Chest Hospital and underwent QFT-GIT testing from October to December 2020 were prospectively included as research subjects, QFT-Plus testing was added. And the basic information, clinical manifestations, laboratory test results, imaging examinations and other data of these patients were collected. A total of 207 patients were included and divided into tuberculosis group and non-tuberculosis group according to these data. There were 124 cases in the tuberculosis group (94 confirmed patients and 30 clinically diagnosed patients), including 90 males and 34 females, aged 18-93 years, with a median age of 57 (38, 67) years. The non-tuberculosis group included 83 patients (16 patients with non-tuberculous Mycobacteria and 67 patients with other lung diseases), including 49 males and 34 females, with a median age of 60 (51, 68) years. The confirmed patients were subdivided into three grades of low, medium and high Mycobacteriam tuberculosis (MTB) bacterial load, and three grades of mild, moderate and severe pulmonary tuberculosis. The results of QFT-Plus and QFT-GIT were compared, and the levels of IFN-γ in different antigen tubes were compared. Differences between different groups were compared using Mann-Whitney U test and Kruskal-Wallis H test. Results: The QFT-Plus showed a high degree of agreement with the QFT-GIT (κ=0.786, 95%CI: 0.740-0.832), while the main discordant result was QFT-GIT negative/QFT-Plus positive, accounting for 15/17. The sensitivity of QFT-GIT was 80.7%(95%CI: 0.706-0.880), the specificity was 76.3%(95%CI: 0.649-0.850), the positive predictive value was 79.8%(95%CI: 0.697-0.873), and the negative predictive value was 77.3%(95%CI: 0.659-0.859), repectively. QFT-Plus showed a sensitivity of 84.3%(95%CI: 0.743-0.910), a specificity of 78.8% (95%CI: 0.679-0.868), and a positive predictive value of 80.5%(95%CI: 0.703-0.879), the negative predictive value being 82.9%(95%CI: 0.721-0.902), slightly improved to that of the QFT-GIT. Also, this study found that there were significant differences in IFN-γ values between different MTB load or disease severity (P<0.05). Conclusions: There is a good consistency between the QFT-Plus test and the QFT-GIT test, both of which show good application value in the auxiliary diagnosis of pulmonary tuberculosis. Moreover, because of the addition of tuberculosis-specific CD8 cell antigen, the QFT-Plus test has higher sensitivity, lower uncertainty and more application value. This study also found that the bacterial load and disease severity of patients with pulmonary tuberculosis may have a certain correlation with the measured value of IFN-γ.
目的： 比较QuantiFERON-TB Gold Plus（QFT-Plus）与QuantiFERON-TB Gold in tube（QFT-GIT）在肺结核辅助诊断中的筛查价值。 方法： 筛检试验。前瞻性纳入2020年10—12月在广州市胸科医院住院的并进行QFT-GIT检测的患者作为研究对象，增加QFT-Plus检测，并收集这些患者的基本信息、临床表现、实验室检测结果和影像检查等资料。共纳入207例患者，分为结核组和非结核组。结核组共124例（包括94例确诊患者和30例临床诊断患者），其中男90例，女34例，年龄18~93岁，中位年龄57（36，66）岁。非结核组共83例（包括非结核分枝杆菌患者16例和其他肺部疾病患者67例），其中男49例，女34例，中位年龄60（51，68）岁。将确诊患者再分为低、中、高MTB荷菌量3级，和轻、中、重度肺结核3级。比较QFT-Plus与QFT-GIT检测结果，对比分析不同抗原管内γ-干扰素水平。各组间的差异采用Mann-Whitney U检验和Kruskal-Wallis H检验进行比较。 结果： QFT-Plus与QFT-GIT检测的结果的一致性较好（κ=0.786，95%CI：0.740~0.832），不一致率仅为8%，不一致的结果主要表现为QFT-GIT阴性/QFT-Plus阳性，占全部不一致的15/17。其中，QFT-GIT检测：敏感度为80.7%（95%CI：0.706~0.880）、特异度为76.3%（95%CI：0.649~0.850）、阳性预测值为79.8%（95%CI：0.697~0.873）、阴性预测值为77.3%（95%CI：0.659~0.859）；而QFT-Plus检测：敏感度为84.3%（95%CI：0.743~0.910）、特异度为78.8%（95%CI：0.679~0.868）、阳性预测值为80.5%（95%CI：0.703~0.879）、阴性预测值为82.9%（95%CI：0.721~0.902），均高于QFT-GIT检测结果。不同结核分枝杆菌荷菌量及疾病严重程度患者之间，抗原管检测的γ干扰素水平差异均有统计学意义（均P<0.05）。 结论： QFT-Plus检测和QFT-GIT检测之间有着较好的一致性，在肺结核的辅助诊断中有良好的应用价值；因为添加了结核特异性CD8细胞抗原，QFT-Plus检测有着更高的敏感度、更低的不确定性和更好的应用价值。本研究还发现，肺结核患者的荷菌量和疾病严重程度可能与γ-干扰素水平有一定相关性。.