A double-blind study of oral salbutamol supplement and repeat sputum smear microscopy in enhancing diagnosis of smear-negative pulmonary tuberculosis in south India.

ABSTRACT

Background: As routine culture facilities are not available in TB control programme in low income countries like India, there is an urgent need to improve the sensitivity of sputum microscopy, especially in diagnosis of smear negative pulmonary TB. Methodology: In a double blind placebo controlled study, the role of repeat sputum microscopy after antibiotics and oral salbutamol supplement in improving the diagnosis of smear negative TB suspects was investigated in an urban TB clinic. We undertook culture examinations for all study patients to find out proportions of TB cases in this series. Results: Of 206 enrolled, (101 salbutamol (S), 105 placebo (P) groups) 26 were positive by repeat sputum smear examination; similar in two groups (S 16, P 10, p = 0.25). In all, 40 (S 23, P 17) including 26 smear- positives, were culture -positive for M. tuberculosis. Conclusions: Two thirds of initially smear negative but culture positive TB patients were smear positive on repeat sputum examination. Thus, repeat sputum smear microscopy for TB suspects improved the diagnosis, nevertheless oral salbutamol therapy was not beneficial. In resource poor settings, repeat sputum smear microscopy after a trial of antibiotics, could significantly improve the diagnosis of smear-negative PTB patients.