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

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Addis Ababa University


Background: Tuberculosis (TB) is an infectious disease caused by the bacillus Mycobacterium tuberculosis. It is the second l eading cau se o f d eath among infectious disease w orldwide. According to FMoH 2013/14 report, the TB case detection rate was 53.7% which is below the target s et f or t he ye ar ( 81.0%). Quality assu red sp utum sm ear microscopy is one of essential components of DOTs to detect TB cases. The quality of AFB smear microscopy often dependent on the s trength of national TB pr ogram that s upport, t rain, a nd m onitor the p erformance of individuals working in the laboratories. Objective: To assess the p erformance o f T B microscopists at E QA r echecking l aboratories i n Ethiopia. Methods: A cr oss sec tional st udy was conducted on 81 EQA rechecking laboratories i n a ll regions of E thiopia from April–July, 2015 . Panel sl ides were prepared a nd va lidated a t the National TB Reference Laboratory (NRL), Ethiopian Public Health Institute (EPHI). Validated panel sl ides an d customized o nsite ev aluation ( OSE) ch ecklist were used t o evaluate t he performance o f m icroscopists at EQ A rechecking l aboratories and th e laboratories. Data w ere 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 T B EQA rechecking laboratories were participated in t he s tudy. Out o f 38 9 study participants; 263 ( 67.6%) were male, 268 ( 68.9%) were f rom hospitals and 241(62%) had gr eater t han f ive ye ars’ w ork experience on T B s mear microscopy services. About 201 (51.7%) participants were BSc degree holders and 319 (82 %) participants were trained in TB s mear microscopy in-service training. The overall performance of professionals scored ≥ 80% was 328(83.3%). The overall sensitivity and specificity in detecting T B ba cilli w ere 84.5% and 93.1 %, respectively. T he o verall p ercent agreement o f participant r eaders w ith reference readers were 87.1 ( kappa= 0.72) w hich w as good a greement. Eighty (20.6%) p articipants c orrectly re ad al l t en sl ides, 156 ( 40.1%) got 90 -95%, 88 ( 22.6%) participants sco red 80-85% a nd 65 ( 16.7%) pa rticipants s cored be low 80%. There were 806 (20.7%) t otal e rrors w hich a ccount 143 ( 3.7 % ) major e rrors a nd 663 ( 17%) minor e rrors. O f 143 major errors; 89 ( 2.3%) were HFN and 54 ( 1.4 %) were HFP errors. O f 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 f or T B c ontrol pr ogram a nd e mphasis s hould be gi ven f or the E QA pr ogram. T B suspected cases may be misdiagnosed and detection rate could be reduced falsely with high risk of t ransmission. Even t hough ga ps w ere not ed on r echecking f acilities, t here w as pr omising performance of those facilities selected for rechecking services during decentralization. Key words: AFB, Quality of AFB microscopy, Rechecking laboratories, EQA, and Level of agreement



AFB,, Quality of AFB microscopy, Rechecking laboratories, EQA