GeneXpert or CBNAAT Based MTB Detection, Assay of Rifampicin Resistance and Comparison with Conventional Methods of Diagnosis

Introduction: GeneXpert is a Cartridge based DNA amplification test. It has high sensitivity and specificity in comparison to conventional methods of diagnosis like ZN staining and culture of Mycobacterium. It is also very rapid in comparison to conventional methods and in single setting MTB detection as well as Rifampicin resistance can be detected through this GeneXpert technique. Material and Methods: Pulmonary and extra pulmonary samples as sputum, BAL, bronchoscopic aspirate, ascetic fluid, CSF, pleural effusion, are used. MTB detection is done with GeneXpert/MTB/RIF assay technique. ZN stain, LJ culture is done with the sample and comparison done with GeneXpert. Results: Total 786 pulmonary and extra pulmonary samples are studied with GeneXpert technique. In which 520 pulmonary and 166 extra pulmonary samples are present. MTB detected in pulmonary samples are 101 (19.4%), in which 18 (n=101) are Rifampicin resistant. In extra pulmonary samples among 166 samples 26(15.6%) are MTB positive and 03(n=26) are Rifampicin resistant. Sensitivity and specificity both are high in GeneXpert than conventional methods of diagnosis like ZN staining and LJ culture.