Diel Roland, Loddenkemper Robert, Meywald-Walter Karen, Gottschalk Rene, Nienhaus Albert
School of Public Health, Heinrich Heine University of Düsseldorf, Düsseldorf.
German Central Committee Against Tuberculosis, Lungenklinik Heckeshorn, HELIOS, Klinikum Emil von Behring, Berlin.
Chest. 2009 Apr;135(4):1010-1018. doi: 10.1378/chest.08-2048. Epub 2008 Nov 18.
Mycobacterium tuberculosis (MTB)-specific interferon-gamma release assays (IGRAs) are an alternative or adjunct to the tuberculin skin test (TST) in identifying recent contacts with latent tuberculosis infection (LTBI), but there are scarce data directly comparing performance of the tests.
To evaluate the agreement between both IGRAs and to determine which contacts were most likely to represent LTBI, the QuantiFERON-TB-Gold In Tube assay (QFT) and the T-Spot.TB test (T-Spot) were compared in TST-positive persons recently exposed to pulmonary tuberculosis cases.
Prospectively enrolled close contacts (n = 812) of 123 culture-confirmed tuberculosis source cases underwent IGRA testing using standardized collected data. Factors independently influencing the risk of MTB infection and their interactions with each other were evaluated by multivariate analysis.
Five variables were found to significantly predict a positive IGRA test result (age, source case acid-fast bacilli positive and/or coughing, cumulative exposure time, foreign origin). There was excellent agreement between the two IGRAs (93.9%, kappa = 0.85), with QFT finding 30.2% of contacts positive and T-Spot finding 28.7%. Assuming positivity to both IGRAs as true infection, sensitivity of the TST at > 10 mm was 72% and at > 15 mm was 39.7%. The use of either IGRA as a replacement for the TST would decrease the number of LTBI suspects to be investigated by approximately 70%.
IGRAs are a more accurate indicator of the presence of LTBI than the TST. Both QFT and T-Spot appear to be valuable public health tools, showing excellent agreement with each other.
结核分枝杆菌（MTB）特异性干扰素-γ释放试验（IGRAs）是结核菌素皮肤试验（TST）用于识别近期潜伏性结核感染（LTBI）接触者的一种替代方法或辅助手段，但直接比较这两种试验性能的数据较少。
为评估两种IGRAs之间的一致性，并确定哪些接触者最有可能代表LTBI，在近期接触肺结核病例且TST呈阳性的人群中比较了全血干扰素-γ释放试验（QFT）和结核感染T细胞检测（T-Spot）。
前瞻性纳入123例经培养确诊的结核病源病例的密切接触者（n = 812），使用标准化收集的数据进行IGRA检测。通过多变量分析评估独立影响MTB感染风险的因素及其相互作用。
发现五个变量可显著预测IGRA检测结果呈阳性（年龄、源病例抗酸杆菌阳性和/或咳嗽、累计接触时间、外国籍贯）。两种IGRAs之间具有极好的一致性（93.9%，kappa = 0.85），QFT检测出30.2%的接触者呈阳性，T-Spot检测出28.7%。假设两种IGRAs均为阳性代表真正感染，TST在> 10 mm时的敏感性为72%，在> 15 mm时为39.7%。使用任何一种IGRA替代TST将使需调查的LTBI疑似病例数量减少约70%。
与TST相比，IGRAs是LTBI存在的更准确指标。QFT和T-Spot似乎都是有价值的公共卫生工具，彼此之间具有极好的一致性。
