Performance of Line Probe Assay (MTBDRplus) in the Detection of Drug Resistance Tuberculosis

Objective/purpose: The development of multidrug resistant tuberculosis and the emergence of extensively and totally drug resistant TB worsen the overall TB control programs. The World Health Organization validates the use of Line Probe Assay (LPA) for rapid detection of MDR-TB. The study evaluates the performance of LPA (MTBDRplus) compared to proportional method (PM). Methods: The study was conducted at TB reference Laboratory, Aminu Kano Teaching Hospital. Using cross-sectional study design 80 Rifampicin Resistant-TB sputum samples were purposely selected and processed according to standard mycobacteriological procedures. Their drug resistance status was detected using PM and MTBDRplus and the performance of LPA were evaluated using MedCalc Software. Results: The study indicated that 88.5% of the samples provided an interpretable result with 46.5% and 30.99% of them detected by LPA and PM as Rifampicin mono resistant. Also, 32.9% and 45.07% of them were MDR-TB by the LPA and PM respectively. Compared to PM, the sensitivity, specificity, PPV and NPV for detection of Rifampicin resistance by the LPA was 98.15%, 82.35%, 94.64% and 93.33% respectively, for detection of Isoniazid resistance was 57.14%, 94.44%, 90.91% and 69.39% respectively, and for detection of MDR-TB resistance was 75.61%, 85.71%, 93.94% and 54.55% respectively. Conclusion: The study demonstrated that the LPA (MTBDRplus) compared to PM performed very high in the detection of Rifampicin resistance more than Isoniazid resistance and MDR-TB. The study identifies the need for improving the MTBDRplus to contain other resistant gene regions to increase the detection rate of not only mono resistant TB but MDR-TB.