Sputum-smear examination in patients with extrapulmonary tuberculosis in Malawi

In Malawi, it has been the practice for several years to obtain sputum for smear microscopy of acid-fast bacilli (AFB) from all patients with extrapul monary tuberculosis (EPTB). We audited this practice, and determined in pat ients aged greater than or equal to 15 years (i) the proportion of EPTB pat ients who had sputum smears examined, (ii) the number of sputum smears exam ined per patient, and (iii) the proportion of patients with EPTB who had sp utum samples smear positive for AFB. Forty-one hospitals (3 central, 22 dis trict and 16 mission) performing smear microscopy and registering EPTB pati ents were visited in 1998 and 1999, and a retrospective and prospective stu dy was carried out using TB registers and laboratory sputum registers. In t he retrospective study, 1124 (69%) of the 1637 patients with EPTB had sputu m smears examined; 988 (88%) of the 1124 submitted 3 sputum specimens. In t he prospective study, 2026 (84%) of the 2411 patients with EPTB had sputum smears examined: 94% of the 2026 submitted 3 sputum specimens. In both stud ies, high rates of sputum submission were found in patients with pleural ef fusion, miliary TB, lymphadenopathy and pericardial effusion. In the prospe ctive study, only 34 (1.7%) EPTB patients submitting sputum were smear posi tive, and the proportion who were smear positive exceeded 3% only in patien ts with lymphadenopathy, miliary TB and TB meningitis. As a result of this study, the Malawi TB Control Programme has changed its policy, and now only insists on sputum-smear examination if patients with EPTB have a cough for >3 weeks. These policy changes will be audited by further operational rese arch.