Validation of the surveillance system for tuberculosis in Botswana

Gaborone and Francistown, Botswana, where surveillance data in the 1997 Electronic Tuberculosis (TB) Register suggest that 39% of pulmonary TB patients did not have pre-treatment sputum smear microscopy performed.

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.

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.

Of 374 patients with pre-treatment sputum smear results missing, 224 (60%) actually had had a sputum smear examined in the laboratory. The proportion of pulmonary TB patients in Gaborone and Francistown who did not have sputum examined was therefore 16% instead of 39%. Most missing results (69%) had not been transcribed from the laboratory results onto the TB Treatment Card. Patients who had a negative smear result or who sought care at a clinic that was different from where their diagnostic evaluation had been initiated were more likely to have missing results.

The actual performance of the Botswana National TB Programme with respect to sputum microscopy examination is much better than surveillance indicators suggest. In addition to sputum collection, proper recording of results needs reinforcement among health care workers to improve routine performance indicators.