Patients with suspicious symptoms of tuberculosis: cough, sputum for more than 2 weeks and hemoptysis or bloody sputum are the main symptoms of tuberculosis. Suspected tuberculosis patients: Anyone who meets one of the following conditions is a suspected case. 1. Children under 5 years of age with suspicious symptoms of tuberculosis, accompanied by a history of close contact with infectious tuberculosis patients or a strong positive tuberculin test; 2. Lesions consistent with active tuberculosis on chest imaging only. Infectious tuberculosis: refers to pulmonary tuberculosis with a positive sputum smear test. Close contacts: persons in direct contact with patients with infectious TB, including family members, colleagues and classmates of the patients. Multidrug-resistant TB: Patients with TB infected with Mycobacterium tuberculosis proven to be resistant to both isoniazid and rifampin at least in vitro. Tuberculosis/HIV co-infection: Active tuberculosis in a person with HIV or AIDS, or HIV infection in a person with tuberculosis.