Validation of the surveillance system for tuberculosis in Botswana

SETTING: Gaborone and Francistown, Botswana, where surveillance data in the 1997 Electronic Tuberculosis (TB) Register suggest that 39% of pulmonary T B patients did not have pre-treatment sputum smear microscopy performed. OBJECTIVE: To determine the proportion of patients with reportedly missing pre-treatment sputum smear results in 1997 who had smears examined, and to identify stages in the system where results were lost. METHODS: Patients with pulmonary TB in 1997 who were missing pre-treatment sputum smear results in the Electronic TB Register were cross-matched with laboratory records; medical records were reviewed. RESULTS: Of 374 patients with pre-treatment sputum smear results missing, 2 24 (60%) actually had had a sputum smear examined in the laboratory. The pr oportion of pulmonary TB patients in Gaborone and Francis- town who did not have sputum examined was therefore 16% instead of 39%. Most missing result s (69%) had not been transcribed from the laboratory results onto the TB Tr eatment Card. Patients who had a negative smear result or who sought care a t a clinic that was different from where their diagnostic evaluation had be en initiated were more likely to have missing results. CONCLUSIONS: The actual performance of the Botswana National TB Programme w ith respect to sputum microscopy examination is much better than surveillan ce indicators suggest. In addition to sputum collection, proper recording o f results needs reinforcement among health care workers to improve routine performance indicators.