Evaluation of the Diagnostic Performance of Genotype MTBDRplus VER 2.0 Line Probe Assay for the Detection of Multidrug Resistance TB (MDR-TB) in Sputum Samples Referred to National TB Reference Laboratory, Ethiopian Public Health Institute
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Date
2015-09
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Addis Ababa University
Abstract
Background: - Accurate and rapid detection of multi drug resistance Tuberculois(MDR-TB) is
critical. Evaluating Genotype MTBDRplus VER 2.0 offer opportunity to scale up drug
susceptibility testing (DST) capacity in Ethiopia.
Objective: - The aim of this study was to evaluate the diagnostic performance of Genotype
MTBDRplus VER 2.0 for the detection of MDR-TB in sputum samples referred to National TB
Reference Laboratory (NTRL) at Ethiopian Public Health Institute (EPHI).
Method and Design: - A cross sectional study was conducted from April to August, 2015 on
presumptive MDR-TB patients. Analysis of 72 smear positive and 197 smear negative sputum
samples was done with Genotype MTBDRplus VER 2.0 assay and compared with the reference,
MGIT 960 culture and DST. Sensitivity, specificity, PPV and NPV of the assay was calculated,
comparing the results with the reference method and results was interpreted based on 95%
confidence interval, statistical significant was taken at p-value <0.05.
Result: - The sensitivity, specificity, PPV and NPV of Genotype MTBDRplus VER 2.0 assay
were 96.4, 100, 100 and 96.9%, respectively for the detection of MDR-TB from direct smear
positive sputum samples. Only 14(54%) samples had valid results with LPA among the 26
smear negative culture positive samples. The sensitivity and specificity of Genotype
MTBDRplus VER 2.0 assay was 100% for the detection of MDR-TB among 14 direct smear
negative and culture positive sputum samples. The most common mutations associated with
RMP and INH resistance was S531L and S315TL, respectively. A single rare mutation
(C15T/A16G) was also detected in this study.
Conclusion and Recommendation: - The diagnostic performance of Genotype MTBDRplus
VER 2.0 assay in direct smear positive sputum sample was highly sensitive and specific for early
detection of MDR-TB. However, the diagnostic performance of Genotype MTBDRplus VER
2.0 assay in direct smear negative sputum sample was low and showed high level of invalid
results so it is unlikely to implement Genotype MTBDRplus VER 2.0 assay for the detection of
MDR-TB in direct smear negative sample in our routine settings.
Key words:- performance, Genotype MTBDRplus VER 2.0, MDR-TB
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Keywords
Performance; Genotype MTBDRplus VER 2.0; MDR-TB