Performance Evaluation of TB Smear Microscopists at External Quality Assessment Rechecking Laboratories in Ethiopia

Background: Tuberculosis (TB) is an infectious disease caused by the bacillus Mycobacterium tuberculosis. It is the second leading cause of death among infectious disease worldwide. According to FMoH 2013/14 report, the TB case detection rate was 53.7% which is below the target set for the year (81.0%). Quality assured sputum smear microscopy is one of essential components of DOTs to detect TB cases. The quality of AFB smear microscopy often dependent on the strength of national TB program that support, train, and monitor the performance of individuals working in the laboratories. Objective: To assess the performance of TB microscopists at EQA rechecking laboratories in Ethiopia. Methods: A cross sectional study was conducted on 81 EQA rechecking laboratories in all regions of Ethiopia from April–July, 2015. Panel slides were prepared and validated at the National TB Reference Laboratory (NRL), Ethiopian Public Health Institute (EPHI). Validated panel slides and customized onsite evaluation (OSE) checklist were used to evaluate the performance of microscopists at EQA rechecking laboratories and the laboratories. Data were captured, cleaned and analyzed by SPSS version 20. Chi square test and kappa values were used for comparison purpose. P value < 0.05 was considerable to statistically significant. Results: A total of 389 laboratory professionals form 81 TB EQA rechecking laboratories were participated in the study. Out of 389 study participants; 263 (67.6%) were male, 268 (68.9%) were from hospitals and 241(62%) had greater than five years’ work experience on TB smear microscopy services. About 201 (51.7%) participants were BSc degree holders and 319 (82 %) participants were trained in TB smear microscopy in-service training. The overall performance of professionals scored ≥ 80% was 328(83.3%). The overall sensitivity and specificity in detecting TB bacilli were 84.5% and 93.1%, respectively. The overall percent agreement of participant readers with reference readers were 87.1 (kappa=0.72) which was good agreement. Eighty (20.6%) participants correctly read all ten slides, 156 (40.1%) got 90-95%, 88 (22.6%) participants scored 80-85% and 65 (16.7%) participants scored below 80%. There were 806 (20.7%) total errors which account 143 (3.7 %) major errors and 663 (17%) minor errors. Of 143 major errors; 89 (2.3%) were HFN and 54 (1.4 %) were HFP errors. Of 663 minor errors; 334 (8.6 %) were LFN, 26 (0.7%) were LFP and 303 (7.8%) were QE. Overall achievements of 81 facilities during onsite evaluation were 85.6% with minimum score of 14.8 % and maximum performance of 98.8%. Greater than 80% of rechecking labs had appropriate facility and safety practice for TB bacilli detection. Conclusion: The overall performance of participants in reading showed good agreement with the reference readers. Overall performance of facilities during onsite evaluation was 85.6%. Overall errors were 20.7% and majority of them were minor errors and the presences of these errors are alarming for TB control program and emphasis should be given for the EQA program. TB suspected cases may be misdiagnosed and detection rate could be reduced falsely with high risk of transmission. Even though gaps were noted on rechecking facilities, there was promising performance of those facilities selected for rechecking services during decentralization.