External Quality Assessment of AFB Smear Microscopy and Associated Factors in Selected Private Health Facilities in Addis Ababa, Ethiopia
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Date
2014-06
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Addis Ababa University
Abstract
Background: Tuberculosis is still public health problem in sub Saharan African countries. In
resource-limited settings, tuberculosis diagnosis relies on sputum smear microscopy, with low and
variable sensitivities, especially in paucibacillary pediatric and HIV-associated TB patients. AFB
smear microscopy laboratories present several weaknesses like overworking, insufficiently trained
personnel, inconsistent reagent supplies, and poorly maintained equipment; thus there is a critical
need for investments in laboratory infrastructure, capacity building, and quality assurance.
Objectives: The main objective of the study was to assess laboratory performance quality of AFB
smear microscopy and its associated factors in selected private health facilities in Addis Ababa,
Ethiopia
Material and Methods: A cross-sectional study conducted in 33 selected private health facilities of
which 7 hospitals, 2 NGO health centers, 23 higher clinics and 1diagnostic laboratory that provide
AFB smear microscopy services in Addis Ababa from January to April 2014. A total of 283 stained
smears were randomly collected for rechecking. 320 slides of panel testing were sent to 32
microscopy centers to evaluate reading, staining and reporting performance of individuals. Check
lists were used to assess quality issues of laboratories. Data were captured, cleaned and analyzed
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using SPSS version 16.0; X tests, kappa values were used for comparison purpose. P value <0.05
was considered to be statistically significant.
Results: Among the 32 participant laboratories, 2 scored 100%, 15 scored 80-95% & the remaining
15 scored 50-75% of overall proficiency test with 10 (3.15) major error and 121 (37.8%) minor
error. The sensitivity, specificity, PPV and NPV of panel reading by microscopy centers were 89%,
96%, 96%, and 90 % respectively. Out of 283 randomly selected slides, the overall false reading for
blinded rechecking was 3.9% with overall agreement of 97.5 % and sensitivity of 88.4 % and
specificity of 99.3%. Of 283 rechecked slides 71.6 % were graded as good evenness, cleanness,
thickness, size, staining and labeling having minimum and maximum score of evenness 161(56.9 %)
and labeling 257 (90.8 %) respectively; having significant difference in slide quality of X2 (p value
<0.05). On-site evaluation indicated problems in terms of infrastructure, standard operating
procedure, reagent quality; equipment maintenance, data management and training issues. Most of
the health facilities had poor microscope maintenance (53.5%) and inventory management (25.0 %)
system.
Conclusion: Microscopy centers scored a panel test score of 75.5% which is below acceptable
minimum score of 80%. In blinded rechecking 3.9% of overall error was committed. In the onsite
checklist, SOP, reagent quality, equipment maintenance, data management & lack of updated
training on AFB microscopy techniques were mentioned as a major bottle neck for quality
performance.
Key words: EQA, panel testing, onsite evaluation, blinded rechecking, major error, minor erro
Description
Keywords
EQA, Panel testing, Onsite evaluation, Blinded rechecking