Role of bronchoscopy in diagnosis of smear-negative pulmonary tuberculosis

Tuberculosis (TB) remains an important cause of morbidity and mortality in many developing countries including India. Prompt and accurate establishment of diagnosis is one of the essential basic principles of care for persons with TB. Sputum smear microscopy and culture remain the cornerstone of diagnosis but can be negative in a substantial proportion of pulmonary TB patients (multiple smear-negative status or scanty sputum). Bronchoscopy has been proven to be a safe and effective method for those patients with varying diagnostic yields ranging from 30 to 90%. Various specimens are obtained from a fiber-optic bronchoscope such as smear and culture for mycobacteria from the bronchial aspirate or wash, bronchoalveolar lavage fluid, bronchial brushing, postbronchoscopy sputum, transbronchial needle aspiration, and transbronchial biopsy. The diagnostic yield is significantly enhanced when nucleic acid amplification testing is applied to bronchoscopic specimens. The role of bronchoscopy in TB diagnosis is likely to be limited because of availability, cost, and logistical challenges. Future studies are needed to better define the role of the newer diagnostic modalities to improve early TB diagnosis.