A positive PPD test means that the patient has been infected with Mycobacterium tuberculosis or has received BCG vaccination, and a positive or strong positive PPD test can only indicate infection with Mycobacterium tuberculosis and cannot be used to diagnose active tuberculosis. Therefore, the PPD test is only a test and a means to detect TB infection, and cannot be used as a basis for confirming the diagnosis. The most definite way to confirm the diagnosis is to detect Mycobacterium tuberculosis by sputum culture, which is the gold standard for the diagnosis of tuberculosis. However, because sputum culture takes a long time, sputum smear is currently the main clinical test for finding Mycobacterium antacidum. Sputum looking for Mycobacterium antacidum is positive, and combined with the clinical symptoms of the patient and the manifestation of CT of the lung, it can be diagnosed as pulmonary tuberculosis.