CBNAAT: Rapid Diagnostic Tool for Detection of Mycobacterium Tuberculosis in Pulmonary Samples

Introduction: Multi drug resistant (MDR) tuberculosis is a major problem worldwide. There is an urgent need to diagnose MDR cases and initiate treatment to interrupt the chain of transmission of Mycobacterium Tuberculosis. Rapid detection of tuberculosis and Rifampicin (RIF) resistance are vital for successful disease management. CBNAAT (Xpert MTB/ RIF) is a fully automated diagnostic test which detects tuberculosis and rifampicin drug resistance simultaneously in few hours. Aim of the Study: The aim of this study was to evaluate the sensitivity and specificity of GeneXpert assay in patients with smear positive and smear negative sputum samples of suspected pulmonary tuberculosis and compared with AFB smear microscopy (ZN staining) Material and Methods: This is an observational study conducted at Community Health Centre, Muradnagar, from January, 2019 to April, 2019. Total 377 patients showing symptoms and signs of pulmonary tuberculosis or having close contact with previously diagnosed tuberculosis patients in the hospital were included in this study. All sputum samples were tested for MTB/RIF detection on GeneXpert. Result: Out of the 377 sputum samples of the patients having signs and symptoms of pulmonary tuberculosis, 145 (38.46%) were MTB positive and 232 (61.53%) were negative. The CBNAAT test identified the agent in 109 out of 114 smear positive sputum samples, and 36 out of 263 sputum smear negative cases. 13 patients out of 377 (3.44%) suspected cases were found to be rifampicin resistant. In our study, overall sensitivity and specificity of GeneXpert were 95.6% and 86.31% respectively which is quite similar with other studies. Conclusion: CBNAAT is a convenientmolecular tool in the identification of pulmonary TB cases because of its easiness and fast turnaround time. It is more viable as compared to AFB smear in the analysis of TB cases and should be routinely utilized for quick detection of TB along with other methods like AFB smear examination and culture DST for better results in the diagnosis of TB.