A strong positive PPD test is likely to indicate active tuberculosis. In general, a positive PPD test indicates tuberculosis infection, but a strong positive test, combined with relevant clinical manifestations, can be considered as a possibility of active tuberculosis, based on sputum testing, clinical manifestations and imaging findings. The sputum test is mainly sputum smear and sputum culture, when the sputum smear is positive for Mycobacterium antacidum, or when the sputum culture is positive for Mycobacterium tuberculosis, the sputum is positive for Mycobacterium tuberculosis. In addition, the clinical manifestations are mainly coughing with sputum and blood in the sputum, or hemoptysis with coughing, and symptoms such as fever, night sweats and fatigue. Chest imaging shows patchy shadows with unclear edges, and there may be central hard nodes, cavities, or disseminated lesions, and chest films show calcification, hard nodes and fibrosis, all of which are diagnostic bases for active tuberculosis.