Objectives: To determine the yield of smear examination under routine conditions in a low income country where tuberculosis is common.
Design: Analysis of routine records in 34 rural smear laboratories using a common, standardized recording system, identified 61,580 tuberculosis suspects with 141, 371 sputum smear examinations. Incremental yield of subsequent sputum smears was determined based on the results obtained in those reported.
Results: The average proportion of cases found among suspects was 19% (range 14-24%). The incremental yield of subsequent sputum smear examinations was estimated to be 83%, 12% and 4% on the three smears examined.
Conclusions: The incremental yield of a third examination, after two have been examined is relatively low. The proportion of suspects found to be positive was higher than previously noted.
