Increased yield of smear positive pulmonary TB cases by screening patients with > or =2 weeks cough, compared to > or =3 weeks and adequacy of 2 sputum smear examinations for diagnosis.

BACKGROUND: RNTCP recommends examining three sputum smears for AFB from Chest Symptomatics (CSs) with cough of > or =3 weeks for diagnosis of Pulmonary TB (PTB). A previous multi-centric study from Tuberculosis Research centre (TRC) has shown that the yield of sputum positive cases can be increased if duration of cough for screening was reduced to > or =2 weeks. Other studies have shown that two smear examinations are adequate for diagnosis of smear positive PTB . To validate the above findings, a cross sectional multi-centric study was repeated in different settings in five geographical areas in India. METHODS: Three primary and secondary level health facilities with high out-patient attendance were selected from two Tuberculosis Units (TU) in each of the 15 selected districts to screen about 10,000 new adult outpatients from each state. For patients who did not volunteer history of cough, symptoms were elicited using a structured simple questionnaire. All the CSs were referred for sputum examination. RESULTS: A total of 96,787 out-patients were registered. Among them 69,209 (72%) were new adult out-patients. Using > or =2 weeks of cough instead of 3 weeks as the criterion for screening, there was an overall increase of 58% in CS and 23% increase in the detection of smear-positive cases. Among 211 patients, 210 were positive at least by one smear from the initial two specimens. Increase in the work-load if 2 smears were done for patients with cough of > or =2 weeks cough were 2 specimens (i.e. 13 to 15) per day for an adult OPD of 150. CONCLUSION: The yield of sputum positive PTB cases can be improved by screening patients with > or =2 weeks cough and two specimens are adequate for diagnosis.