Objective:To combine the detection of serum levels of adenosine deaminase (ADA) and T-cell spot test (T-spot.TB),and to explore their significances in diagnosis of pulmonary tuberculosis.Methods:159 patients suspected with pulmonary tuberculosis were selected and divided into pulmonary tuberculosis group and non-tuberculosis group (n=68);80 healthy people were randonly selected as healthy control group.The serum ADA levels and number of T-spot of the subjects in three groups were detected.Ther serum ADA levels and the positive rates of T-spot.TB in various groups and their sensitivities and specifities were compared. Results:The serum ADA level of the patients in pulmonary tuberculosis gruop was (22.10±6.60)U·L-1;those in non-tuberculosis group and healthy control group were (16.90±6.35)and (8.70±5.98)U·L-1;the serum ADA level in pulmonary tuberculosis group was significantly higher than those in non-tuberculosis group and heathy control group (P<0.05).The positive rate of serum ADA level in diagnosis of pulmonary tuberculosis was 56% and the T-spot.TB positive rate in diagnosis of pulmonary tuberculosis was 87.9%. Combined use of parallel test, the detection sensitivity was 91.2%;using the series of joint tests,the specificity was 94.6%.Conclusion:Combined detection of serum level of ADA and T-spot.TB can significantly improve the clinical diagnosis efficacy of pulmonary tuberculosis.