Evaluation of GeneXpert MTB/RIF assay as a potential diagnostic tool of Mycobacterium tuberculosis (MTB) in Chittagong metropolitan city

Aims: Precise diagnosis of Mycobacterium tuberculosis (MTB) is key to treating and managing tuberculosis (TB) patients effectively. This study was carried out to evaluate the performance of the GeneXpert MTB/Rif assay and compare its efficiency with other conventional TB detection methods. Methodology and results: In total, 110 samples were collected from pulmonary presumptive TB patients in Chittagong metropolitan city and subjected to GeneXpert MTB/RIF assay, MTB culture and microscopic examination to compare their performance in the diagnosis of TB. The sensitivity, specificity, and positive and negative predictive values (PPV, NPV) of these methods were calculated using culture as the reference method. The TB-positive results found for GeneXpert, ZN staining, Auramine O staining and culture were 30 (27.27%), 21 (19.09%), 26 (23.64%) and 18 (16.36%), respectively. GeneXpert showed higher sensitivity (100%) than that of ZN stain (44.44%) and Auramine O stain (72.22%). Moreover, the specificity for detecting MTB in sputum samples observed for GeneXpert was 86.96%, whereas ZN and Auramine stain showed similar specificity (85.86%). Conclusion, significance and impact of study: In this study, GeneXpert was found as the rapid and sensitive method for early detection of MTB compared to other diagnostic methods. Identification of MTB by GeneXpert assay might improve the quality and reduce the time of diagnosis in developing countries like Bangladesh.