Effectiveness of CBNAAT in the Diagnosis of Sputum Negative Tuberculosis

摘要

Introduction: Tuberculosis (TB), caused by the bacterium Mycobacterium tuberculosis, remains one of the major health problems in India. Early detection of TB and Rifampicin (RIF) resistance are essential for effective disease management. The recent introduction of Cartridge-Based Nucleic Acid Amplification Test (CBNAAT) also known as Gene Xpert MTB/ RIF assay has significantly transformed the diagnostics of TB. Aim: To evaluate the role of CBNAAT and smear microscopy by Ziehl-Neelsen (ZN) staining in the diagnosis of Pulmonary Tuberculosis (PTB). Materials and Methods: Sputum samples from 337 patients having symptoms suggestive of PTB were included in this study. Sputum samples for ZN staining and CBNAAT were processed. RIF resistance was detected by CBNAAT. Results: Out of 337 samples, 36 (10.68%) sputum samples were positive by smear microscopy. Samples from 107 cases with high clinico-radiological presumption were subjected to CBNAAT examination, out of which 41 (38.31%) were confirmed positive microbiologically. The mean age was 45±18.30 years, 24% were females and 76% were males. Overall sensitivity of CBNAAT was 38.31%. Sensitivity of CBNAAT was 100% for sputum positive cases and sensitivity was 15.38% for sputum negative cases. Overall RIF resistance was detected in two (1.86%) cases in present study. Conclusion: CBNAAT helps in early detection to diagnose PTB. It can be used for screening MDR-TB for starting anti-tubercular treatment early.