Microscopic detection of Mycobacterium tuberculosis in direct or processed sputum smears.

Introduction: Microscopic identification of active pulmonary tuberculosis (PTB) from direct smears of sputum (DS) is widely used for detection, but has limited sensitivity. Here, we assessed the yield of acid-fast bacilli (AFB) detection in processed sputum smears (PSS).

Methods: Sputum samples were simultaneously analyzed by direct sputum smearing and after chemical treatment and spontaneous sedimentation.