摘要Background:Interferon-gamma release assay (IGRA) has been used in latent tuberculosis (TB) infection and TB diagnosis,but the results from different high TB-endemic countries are different.The aim of this study was to investigate the value of IGRA in the diagnosis of active pulmonary TB (PTB) in China.Methods:We conducted a large-scale retrospective multicenter investigation to further evaluate the role of IGRA in the diagnosis of active PTB in high TB-epidemic populations and the factors affecting the performance of the assay.All patients who underwent valid T-SPOT.TB assays from December 2012 to November 2015 in six large-scale specialized TB hospitals in China and met the study criteria were retrospectively evaluated.Patients were divided into three groups:Group 1,sputum culture-positive PTB patients,confirmed by positive Mycobacterium tuberculosis sputum culture;Group 2,sputum culture-negative PTB patients;and Group 3,non-TB respiratory diseases.The medical records of all patients were collected.Chi-square tests and Fisher's exact test were used to compare categorical data.Multivariable logistic analyses were performed to evaluate the relationship between the results of T-SPOT in TB patients and other factors.Results:A total of 3082 patients for whom complete information was available were included in the investigation,including 905 sputum culture-positive PTB cases,914 sputum cultmre-negative PTB cases,and 1263 non-TB respiratory disease cases.The positive rate of T-SPOT.TB was 93.3％ in the culture-positive PTB group and 86.1％ in the culture-negative PTB group.In the non-PTB group,the positive rate of T-SPOT.TB was 43.6％.The positive rate of T-SPOT.TB in the culture-positive PTB group was significantly higher than that in the culture-negative PTB group (x2 =25.118,P ＜ 0.01),which in turn was significantly higher than that in the non-TB group (x2 =566.l 16,P ＜ 0.01).The overall results were as follows:sensitivity,89.7％;specificity,56.37％;positive predictive value,74.75％;negative predictive value,79.11％;and accuracy,76.02％.Conclusions:High false-positive rates of T-SPOT.TB assays in the non-TB group limit the usefulness as a single test to diagnose active TB in China.We highly recommend that IGRAs not be used for the diagnosis of active TB in high-burden TB settings.