Comparison of Induced Sputum and Bronchoalveolar Lavage Fluid Examination in the Diagnosis of Sputum Negative Pulmonary Tuberculosis

Abstract

Tuberculosis (TB) is one of the common infections in the world, especially in developing countries like India. Therefore, early diagnosis is important. This study was undertaken to compare the yield of sputum, induction with bronchoalveolar lavage (BAL) in smear-negative suspected pulmonary TB patients in a tertiary care hospital in Agra. Fifty patients were included in the study. In all patients, induced sputum, fibreoptic bronchoscopy and BAL fluid were subjected to diagnostic testing. On acid-fast smear examination, induced sputum and BAL fluid tested positive in 27/50 and 25/50 patients, respectively with a sensitivity of 83.3% and 90% respectively (p<0.0001). On comparing sputum induction versus BAL on culture, 30 patients were positive by sputum induction and 27 patients were positive on BAL fluid, with the sensitivity of 85.7% and 77.1%, respectively. The results showed that the sputum induction showed a significantly higher yield than that of BAL fluid (p=0.0013). Sputum induction offers an alternative approach in the diagnosis of smear-negative suspected pulmonary TB patients and would enhance sensitivity for the diagnosis of TB.