Background: Mycobacterium Tuberculosis (TB) detection through quality assured laboratories is an essential element of the World Health Organization (WHO) STOP TB Strategy. For this quality assurance of acid fast bacilli (AFB) stained sputum smear microscopy is essential as AFB Microscopic diagnosis has remained the routine laboratory method for the identification of TB in Ethiopia. This study intended to assess the performance of laboratory professionals in detecting TB bacilli at Hawassa and Hawassa Zuriya health institutions.

Methods: A cross-sectional study design was employed on a total of 67 laboratory professionals working in public health facilities. A standardized pre-validated panel slide and questionnaires were distributed to laboratory professionals along with on-site evaluation by using standard questioner. A total of ten slides per panel given for each professional. Each panel of slides includes 4 negative slide and 6 positive slides of different bacterial density (3 with 1-9 AFB/100 fields, one with 1+ one with 2+ andone with3+). Agreement in detecting of TB bacilli Sensitivity, specificity and predictive values of readings were assessed using SPSS version 20.0

Results: Onsite evaluation showed that about 89% of laboratories has no separate area for TB work as well as 78% have no adequate ventilation very far from the standard Laboratory safeties. Nineparticipants (13.4%) correctly reported all panel slides. A total of 13.74%(92/670) errorwasreported thatincludema jorerrors of 1.04% (5HFN; 2 HFP) and minor errorsof12.70 %(17 LFN and LFP each,and51QE).The sensitivity, specificity, positive predictive values (PPV) and negative predictive value (NPV) of participants in detecting TB bacilli as compared to the reference reading were 94.52%, 92.91%, 95.23% and 92.67% respectively.

Conclusion: laboratory safeties are deficient on most laboratories and there are a lot of technical problems observed during on-site observation. Agreement of the participants with reference reading in the detection of TB bacilli was very good according to national guide line. Though low major error were reported, training and supervisory activities are still important for successful TB control programs.