The concept of bacillus-negative tuberculosis Bacillus-negative tuberculosis refers to active tuberculosis with at least three sputum smears and one negative sputum culture, which is non-infectious tuberculosis. Because of the lack of the gold standard for TB diagnosis “sputum positive”, the diagnosis of bacillus-negative TB has always troubled clinicians, and the lack of characteristic clinical manifestations in many patients has easily led to misdiagnosis and missed diagnosis. Clinical features of bacillary tuberculosis Bacillary tuberculosis is common in the early stages of tuberculosis, and can also be seen in those with milder lesions, therefore, most patients with bacillary tuberculosis have mild clinical symptoms, some even have no symptoms, and many patients are found only through physical examination. Some patients only have fatigue and lethargy, and it is not uncommon to have low fever in the afternoon and night sweats. Respiratory symptoms such as cough, sputum, hemoptysis and dyspnea are also rare, and a small number of patients may have chest pain and tightness. It should be reminded that some lesbians may have irregular menstruation or even amenorrhea; children may have personality changes such as irritability and irritability. Some patients may be mistaken for having a cold and be ignored. X-ray examination of bacillary tuberculosis often shows cloudy, lamellar, or speckled shadows in the lungs, mostly in the posterior segment of the upper lobe and the dorsal segment of the lower lobe, which are not easily distinguished from other infectious lesions in the lungs. In some cases, the lesions may appear as spherical lesions less than 3 cm in diameter, which can be easily confused with tumors of the lung. Diagnostic points of bacillary tuberculosis: (1) typical clinical symptoms of tuberculosis and chest X-ray; (2) effective anti-tuberculosis treatment; (3) clinical exclusion of other non-tuberculous lung diseases; (4) detection of acid-resistant bacilli in bronchoalveolar lavage fluid (BACF); (5) histopathological examination of bronchi or lungs to confirm tuberculous changes; (6) strong positive skin test for tuberculosis (PPD 5u) (7) positive PCR plus probe test for sputum Mycobacterium tuberculosis; (8) extra-pulmonary histopathological examination to confirm tuberculosis lesions. The presence of pulmonary lesions and the diagnosis of bacillus-negative tuberculosis is based on items 1 to 5 as the main indicators and items 6 to 8 as reference indicators. The diagnosis is confirmed by the presence of three of items 1 to 6 or any one of items 7 to 8. Treatment of bacillary-negative tuberculosis Treatment of bacillary-negative tuberculosis must also comply with our principles of early, combination, appropriate, regular, and full chemotherapy to achieve the goal of rational chemotherapy. However, in some cases, targeted individualized medication should be given based on clinical manifestations and specific monitoring data. The susceptible groups of tuberculosis: close contacts of patients with bacillary tuberculosis; children who have not received BCG vaccination; people who come to Tianjin for schooling or work in remote areas; recent positive tuberculin test, positive reaction in children under 3 years old, strong positive reaction in children under 15 years old; previous pulmonary tuberculosis or untreated or irregularly treated extrapulmonary tuberculosis; recurrent colds or untreated; infectious lesions in the lungs, ineffective anti-infective treatment or poor efficacy; overexertion, irregular lifestyle, malnutrition, mental trauma; diseases associated with TB: diabetes, post-gastrectomy, application of adrenocorticotropic hormones and other immunosuppressive agents, human immunodeficiency virus infection, etc. These are the people who are of concern for the diagnosis of tuberculosis. diagnosis and exclude other pulmonary diseases; 5. Induced sputum examination; 6. Bronchoscopy: smear, aspirate, washing fluid, alveolar lavage fluid, brush examination, biopsy and postoperative sputum examination for bacteriological and histocytological examination; 7. Molecular biology diagnosis: polymerase chain reaction (PCR); 8. Pathological examination; 9. Diagnostic test treatment.