Screening tuberculosis suspects using two sputum smears

SETTING: Ntcheu district hospital, Malawi. OBJECTIVE: To assess a screening strategy for tuberculosis (TB) suspects us ing two sputum smears. DESIGN: A strategy of screening all TB suspects with two sputum smears for 6 months (1 July-31 December 1998) was compared with the period 1 January t o 30 June 1998 during which the strategy of screening TB suspects with thre e sputum smears was in use. All chest radiographs of patients with negative sputum smears were assessed, and in those with pulmonary cavities and exte nsive disease a third sputum smear was examined. Data were collected from t he laboratory sputum register and the TB register. The two 6-month periods were compared. RESULTS: In the laboratory register, using a two-sputum strategy, 186 (16%) of 1152 TB suspects were smear-positive, a result that was no different th an when the three-sputum strategy was used, where 173 (16%) of 1106 TB susp ects were smear-positive. The clinical pattern of TB using the different sc reening strategics was similar, with 58% of registered patients smear-posit ive with the two-sputum strategy and 54% smear-positive with the three-sput um strategy. In the first 6 months 3177 sputum smears were examined compare d to 2266 smears in the second 6 months, a 29% reduction in the number of s mears examined. The cost of consumables using the strategy of three sputum smears was USD $731 compared with USD $521 using the strategy of two sputum smears. CONCLUSIONS: Screening TB suspects using two sputum smears is as effective as screening using three sputum smears, and is associated with less laborat ory work and savings in costs.