the value of bronchoalveolar lavage in the diagnosis of sputum smear-negativepulmonary tuberculosis

background and objectives: sputum smear staining for acid-fast bacilli is initial approach to the diagnosis of pulmonary tuberculosis (ptb) but more than 50% of cases are sputum smear-negative. this study was aimed to investigate the diagnostic value of fiberoptic bronchoscopy (fob) guided bronchoalveolar lavage (bal) in patients suspected to have tuberculosis. methods: this prospective cross-sectional study was carried out on 290 sputum smear-negative patients who were clinically suspicious for ptb in 2006-12. all patients were subjected to fob andbal, then bal specimens stained and cultured. results: of the 290 patients, 173 cases (59.7%) were men and 117 cases (40.3%) were women with the age of 52.6±19.1 years (ranged 20-76 years). of the total 290 bal specimens, 110 specimens (38%) were positive for acid-fast bacilli. sensitivity, specificity, ppv and npv was 60%, 91%, 89% and 64%, respectively. also, lr+ and lr- was 64.6% and 0.44%, respectively. conclusion: fob guided bal is a reliable, rapid and useful method for establishing the diagnosis of smear negative ptb with minimal complications.