Comparative analysis of OPD case screening with varying cough duration and sputum samples for diagnosis of tuberculosis in chest symptomatic attending the OPD.

Research Question: Can we minimize cough duration and number of sputum samples in chest symptomatic for screening of TB Objectives: To evaluate cough of three weeks vs. two weeks duration using two sputum samples vs. three samples in chest symptomatic attending the opd. Study Design: Hospital based cross-sectional study. Study Period: December 2006 to May 2008. Methods: Outpatients (2810) with H/O cough three weeks duration and cough of two weeks duration were screened by subjecting to sputum microscopy for tuberculosis using two sputum samples as well as three samples following standard procedure for sputum collection, staining and AFB identification. Those on drugs were not included Results: Using ≥2 week cough, sputum positivity rate was 12%, nearly as high as the sputum positivity among patients with ≥ 3 week cough i. E; 14%. First sputum smear alone on an average could detect 91.8% cases while first two sputum smears could detect on an average 96% cases. Maximum number of cases were diagnosed by only 2 sputum smears & added diagnostic value of 3rd specimen was small (4%). Higher sputum positivity rate using ≥2 week cough with 2 sputum samples was seen in age groups below 35, in females and in those with H/O contact & or family H/O tuberculosis. However, sensitivity, specificity & overall yield results of using ≥ 2 week cough with 2 sputum samples did not differ much from all other combinations & permutation of cough duration & number of sputum samples. Conclusions: The validity of screening of chest symptomatic for sputum examination showed that using ≥ 2 week cough with 2 sputum samples gives similar results as ≥ 3 week cough with 3 sputum samples but this needs further confirmation by culture method. Hence, using of ≥ 2 week cough with 2 sputum samples as diagnostic criteria for screening of cough symptomatic for TB should be recommended as one way of improving efficient use of scarce resources