Screening tuberculosis suspects: How many sputum specimens are adequate?

Background: The aim of the study was to assess whether the number of sputum samples for screening of tuberculosis suspects could be minimized. Materials and Methods: It was a hospital-based cross-sectional study conducted from December 2006 to May 2008. Chest symptomatic 2810 patients were screened for tuberculosis (TB) by subjecting them to sputum microscopy using 2 sputum samples as well as 3 samples following standard procedure for sputum collection, staining, and AFB identification. Results: First sputum smear alone could detect 91.8% cases while first 2 samples together could detect 96% cases. Maximum no. of cases were diagnosed by only 2 specimen sputum smears, and added diagnostic value of third specimen was small i.e., 4%. Conclusions: Hence, 2 sputum samples as diagnostic criteria for screening of TB suspects is one way of improving the efficient use of scarce resources.