Comparative analysis of case screening with varying cough duration and sputum samples for diagnosis of tuberculosis in patients attending the OPD at a tertiary care hospital at Srinagar, India

Research Question : Can we minimize cough duration and number of sputum samples in chest symptomatic patients for screening of TB? Objective : To evaluate cough of 3 weeks versus 2 weeks duration using two sputum samples versus three samples in chest symptomatic patients attending the OPD. Study Design : Hospital-based cross-sectional study. Materials and Methods : Outpatients (2810) with H/O cough of 3 weeks and 2 weeks duration were screened by subjecting them to sputum microscopy for tuberculosis using two sputum samples as well as three samples following standard procedure for sputum collection, staining and acid-fast bacillus (AFB) identification. Those on drugs were not included. Results : Using .2 weeks cough, sputum positivity rate was 12%, nearly as high as the sputum positivity among patients with .3 weeks cough, i.e. 14%. First sputum smear alone on an average could detect 91.8% cases, while the first two sputum smears could detect on an average 96% cases. The study showed that maximum number of cases was diagnosed by only two sputum smears and added diagnostic value of third specimen was small, i.e. 4%.High sputum positivity rate using .2 weeks cough with two sputum samples was seen. Conclusion : The sensitivity analysis of the study showed that using .2 weeks cough with two sputum samples gives almost similar values as .3 weeks cough with three sputum samples, but this needs further confirmatory results of culture sensitivity. Hence, using .2 weeks cough with two sputum samples as the diagnostic criteria for screening of cough patients for TB should be recommended as one way of improving efficient use of scarce resources.