Performance Evaluation of TB Smear Microscopists at External Quality Assessment Rechecking Laboratories in Ethiopia
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Date
2015-09
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Addis Ababa University
Abstract
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
Description
Keywords
AFB,, Quality of AFB microscopy, Rechecking laboratories, EQA