Induced Sputum- as a Diagnostic Tool for Pulmonary Tuberculosis

Background: In developing countries like India where there is very high prevalence of TB and TB HIV co-infection microbiological confirmation of pulmonary tuberculosis (TB) is of paramount importance. Objectives: To assess the significance of sputum induction (SI) with hypertonic saline nebulization as a diagnostic tool in patients with suspected pulmonary TB who have no/inadequate sputum or have sputum smear negative for acid fast bacillus (AFB). Materials and Methods: Total eighty patients clinically and radiologically suspected of pulmonary TB with no/inadequate sputum or have sputum smear negative for acid fast bacillus (AFB) with spontaneous sputum were studied. Sputum was induced with 20 ml of 3% hypertonic saline solution delivered through nebulizer. The specimens were subjected to Ziehl Neelsen staining and were examined under oil immersion lens for the presence of AFB. The specimens were also subjected to mycobaterial culture in BACTEC 460 TB system. Results: Seventy six patients could produce adequate sputum after SI. Sputum from thirty two patients were found to be positive both in smear and culture while sputum from another three patients were smear negative, but culture positive. Conclusion: SI is a safe, cheap and non-invasive procedure and provides significant yield in the diagnosis of pulmonary TB; thus, increasing the case detection rate of smear positive pulmonary TB.