Microscopic detection of Mycobacterium tuberculosis in direct or processed sputum smears

ABSTRACT

Abstract 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. RESULTS: Of the 1,719 samples analyzed, 16.4% were positive for AFB in conventional DS and 21.4% in PSS, corresponding to a 30% increase in detection. CONCLUSIONS: Increased sensitivity from analyzing PSS and better safety protocols will contribute to improved detection and control of the disease.