Performance evaluation of laboratory professionals on tuberculosis microscopy at Hawassa Town, Southern Ethiopia

Microscopic diagnosis of Ziehl-Neelsen stained sputum by microscopists has remained the best routine laboratory method for the diagnosis of tuberculosis (TB). However, detection and identification of TB require skilled laboratory personnel. The aim of the study was to assess the performance of laboratory professionals in detecting TB bacilli at Hawassa town health institutions. A cross-sectional study design was employed among a total of 81 laboratory professionals working in public and private health facilities. A standardized pre-validated slide panel and questionnaires were distributed to laboratory professionals. Agreement in detection of TB bacilli sensitivity, specificity and predictive values of readings were assessed using SPSS version 16.0. Among the 81 participant, 11(13.6%) correctly reported all panel slides, 70 (86.4%) missed at least one slides. A total of 29.75% (241/810) error was reported that include major errors of 2.22% (13 HFN; 5 HFP) and minor errors of 27.5% (25 LFN; 60 LFP and138 QE). The sensitivity and specificity of participants in detecting TB bacilli as compared to the reference reading were 91.97, 80.00, 87.30 and 86.92%, respectively. Overall agreement of participants with the reference reading on TB detection was 95.18% (Kappa = 0.73). Agreement of the participants with reference reading in the detection of TB bacilli was good. Even though the study revealed only 2.22% major error, the laboratory professionals need continuous supervision and remedial actions on time for successful TB control programs.