In our study, the optimum cut-off point of ADA for distinguishing tuberculosis and non-tuberculosis subjects was found to be >24 U/L using the ROC curve and has low sensitivity, high specificity in tuberculosis patients that indicated this test do not have enough sensitivity to assist in the diagnoses of tuberculosis patients from other respiratory diseases and not evaluated perform well enough to replace sputum smear microscopy. The gene discussed is ADA; the disease is respiratory system disorder.