涂阳肺结核患者γ-干扰素释放试验假阴性的影响因素分析

目的分析γ-干扰素释放试验(IGRA)检测痰涂阳肺结核患者出现假阴性结果的影响因素。方法搜集2019年6-12月就诊于西安市胸科医院的196例痰涂阳肺结核患者作为研究对象,其中,男145例(74.0%),女51例(26.0%);年龄中位数(四分位数)[M(Q₁,Q₃)]为38(26,53)岁。按IGRA检测结果分为IGRA检测阳性组(106例)和假阴性组(90例)。收集研究对象一般资料、临床症状、实验室检验资料,以及胸部CT表现,采用多因素logistic回归分析IGRA检测痰涂阳肺结核患者出现假阴性结果的影响因素。结果 196例研究对象中,IGRA检测阳性106例,阳性率为54.1%。IGRA阳性组白细胞计数的M(Q₁,Q₃)为6.3(5.0,7.5)×10⁹个/L,低于IGRA假阴性组的7.4(5.8,9.2)×10⁹个/L,差异有统计学意义(Z=-3.464,P=0.001);血红细胞沉降率的M(Q₁,Q₃...

Analysis on risk factors associated with false negative results of interferon-gamma release assay in active tuberculosis

Objective To analysis risk factors associated with false negative result of interferon-gamma release assay (IGRA) in pulmonary tuberculosis with positive sputum smear. Methods A total of 196 pulmonary tuberculosis patients with positive sputum smear were collected from June to December 2019 in Xi’an Chest Hospital, including 145 males (74.0%) and 51 females (26.0%); the median age (M(Q₁,Q₃)) was 38 (26, 53) years. They were divided into IGRA positive group (n=106) and false negative group (n=90). Data of general information, clinical symptoms, results of laboratory test and chest CT findings were collected. Multivariate logistic regression analysis was used to analyze the risk factors associated with false negative result of IGRA in pulmonary tuberculosis patients with positive sputum smear. Results Among the 196 patients, 106 cases were IGRA positive (54.1%). The white blood cell count (M(Q₁,Q₃)) of IGRA positive group was 6.3 (5.0, 7.5)×10⁹ cells/L, which was statistically lower than that of IGRA false negative group (7.4 (5.8, 9.2)×10⁹ cells/L) (Z=-3.464, P=0.001); the erythrocyte sedimentation rate (M(Q₁,Q₃)) in IGRA positive group was also statistically lower than that in IGRA false negative group (34.5 (16.0,58.0) mm/1 h vs. 53.0 (31.8, 84.3) mm/1 h, Z=-3.492, P=0.000); however, the number of CD4⁺T lymphocytes in IGRA positive group was statistically higher than that in IGRA false negative group (553 (371,737) cells/μl vs. 432(320, 645) cells/μl, Z=-2.080, P=0.038). Using multivariate logistic regression analysis, it was showed that white blood cell count ≥7.0×10⁹ cells/L (OR(95%CI)=3.003 (1.618-5.572)), erythrocyte sedimentation rate ≥40mm/1 h (OR(95%CI)=2.270 (1.228-4.195)), CD4⁺T cell <400 cells/μl (OR(95%CI)=2.198(1.155-4.181)) were dependent risk factors for false negative result of IGRA in pulmonary tuberculosis with positive sputum smear. Conclusion The increase of white blood cell and erythrocyte sedimentation rate, as well as the decrease of CD4 ⁺T cell are dependent factors for false negative result of IGRA, the clinical application of IGRA to aid tuberculosis diagnosis should combine with other factors of patients.