Diagnostic definition of bacillus-negative tuberculosis: bacillus-negative tuberculosis is tuberculosis with three sputum smears and one negative culture. The diagnostic criteria are: 1. Typical clinical symptoms of TB and chest x-ray performance. 2. Effective anti-tuberculosis treatment. 3. Other non-tuberculous lung diseases can be excluded clinically. 4. Strongly positive PPD (5TU); positive serum anti-tuberculosis antibody. 5, sputum TB bacilli PCR + probe test is positive. 6.Extrapulmonary histopathology confirmed tuberculosis lesion. 7.BALF detects acid-resistant branching bacilli. 8.Bronchial or pulmonary histopathology confirmed tuberculosis lesion. The diagnosis can be confirmed by having 3 of items 1 to 6 or any 1 of items 7 to 8.