The 124 patients with pleural effusion which were suspected as having suspected MTB infection were enrolled. T-SPOT was used to detect the immune response of peripheral blood lymphocyte against MTB special secreted protein EAST-6 and CFP-10. The MTB DNA method was used to detect MTB in pleural effusion, meanwhile serum anti-MTB antibody was detected by immuno-gold filtration assay, and the results were analyzed statistically.

The 44 of 124 cases were diagnosed as tuberculosis by sputum, pleural effusion and ascites smear test, sputum, pleural effusion and ascites MTB culture, tuberculin test, MTB DNA method and anti-MTB antibody test, and the positive rate was 35.5%. The positive rate of T-SPOT in the 124 patients with pleural effusion was 33.06%(41/124). The positive rate of MTB DNA method was 14.52%(18/124), and that of anti-MTB antibody test was 9.68%(12/124). Among the 44 confirmed tuberculosis patients, T-SPOT had the consistency rate of 86.36%(38/44), while the consistency rates of MTB DNA method and anti-MTB antibody test were 27.27%(12/44) and 18.18%(8/44), respectively. The positive rate and consistency rate of T-SPOT were significantly higher than those of the others (P<0.05). The positive and negative predictive values of T-SPOT in suspected MTB infected patients with pleural effusion were 92.68% and 92.77%, respectively.

T-SPOT is fast, sensitive and specific to diagnose the suspected MTB infected patients with pleural effusion. T-SPOT is better than MTB DNA method and anti-MTB antibody test. T-SPOT can become a new diagnostic method to be applied in the diagnosis of MTB infection.