Abstract： Objective To evaluate the application of interferon-γ release assay T-SPOT.TB in diagnosis and efficacy assessment of pulmonary tuberculosis. Methods T-SPOT.TB assay was used to determine spot-forming cells (SFCs) formed by T-cells when stimulated by Mycobacterium tuberculosisspecific antigens in 55 patients with active tuberculosis,14 patients with non-tuberculosis lung diseases and 12 healthy controls. Meanwhile 20 sputum culture-positive and qualitative assay-positive pulmonary tuberculosis patients were tested with T-SPOT.TB before and at 2-month and 6-month after treatment.Kruskal-Wallis H and Mann-Whitney U test were used in group comparison.Wilcoxon test was used in comparison between pre- and post-treatment.Results The positive rate of T-SPOT.TB was significantly higher in patients with tuberculosis (85.5％,47/55 ) than that in patients with non-tuberculosis lung diseases (2/14) and the healthy controls (1/12) (x2 =40.926,P ＜0.05).The SFCs of hole A in response to ESAT-6 and hole B in response to CFP-10 in pulmonary tuberculosis group were 70.00 (27.00 -125.00) and 80.00 ( 17.00 - 180.00),respectively,which were all significantly higher than those in nontuberculosis lung diseases group and the healthy controls (x2 =35.376 and 30.485,P ＜ 0.05 ).The sensitivity,specificity,positive predictive value and negative predictive value of T-SPOT.TB in diagnosis of smear-positive tuberculosis were 88.6％,88.5％,91.2％ and 85％,while in diagnosis of sputum smearnegative tuberculosis,the sensitivity was 80％,specificity was 88.5％,positive predictive value was 84.2％ and negative predictive value was 85.2％ ( P ＞ 0.05 ).SFCs of hole A and hole B in 20 patients with sputum culture-positive and qualitative assay-positive pulmonary tuberculosis were 75.50 (41.25 -116.25 ) and 56.25 ( 105.00 -225.00) before the treatment.After 2-month antituberculosis treatment,the SFCsofhole A and hole B were 41.0 (18.0-68.75) and 72.50 (42.25- 158.75),which were significantly lower than those before treatment (Z =- 3.213 and - 3.622,P ＜ 0.05 ).Ater 6-month antituberculosis treatment,the SFCs of hole A and hole B were 25.00 (5.75 - 52.25) and 55.00 (6.25 -122.50),which were significantly lower than those before and 2-month after antituberculosis treatment (vs.before treatment:Z =- 3.921 and - 3.923,P ＜ 0.05 ; vs.2-month antituberculosis treatment:Z =- 3.926 and - 3.884,P ＜ 0.05 ).Conclusions T-SPOT.TB assay possess satisfactory sensitivity and specificity in diagnosis of tuberculosis infection,especially for sputum-negative pulmonary tuberculosis.It is also of value in monitoring antituberculosis treatment.