Indian Journal of Respiratory Care

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VOLUME 12 , ISSUE 1 ( January-March, 2023 ) > List of Articles

Original Article

Utility of GeneXpert MTB/RIF in the Rapid Diagnosis of Extra Pulmonary Tuberculosis

Praful S Patil, Dhruba H Chandi, Ashok Rangaiahagari

Keywords : Extrapulmonary tuberculosis, GeneXpert MTB/RIF test, Real-time polymerase chain reaction

Citation Information : Patil PS, Chandi DH, Rangaiahagari A. Utility of GeneXpert MTB/RIF in the Rapid Diagnosis of Extra Pulmonary Tuberculosis. Indian J Respir Care 2023; 12 (1):46-48.

DOI: 10.5005/jp-journals-11010-1003

License: CC BY-NC-SA 4.0

Published Online: 14-03-2023

Copyright Statement:  Copyright © 2023; The Author(s).


Introduction: The diagnosis of extrapulmonary tuberculosis (EPTB) is a challenge. World Health Organization (WHO) recommends the use of GeneXpert MTB/RIF assay [Cepheid, United States of America (USA)], using a heminested real-time polymerase chain reaction (PCR) to amplify a Mycobacterium tuberculosis-specific sequence of the rpoB gene for the rapid and simultaneous detection of M. tb complex (MTBC) and resistance to rifampicin from a clinical specimen. The purpose of this study is to evaluate the performance of the GeneXpert MTB/RIF test with conventional mycobacterial culture in EPTB specimens. Materials and methods: This prospective study (February–October 2017, 11 months) includes data on 287 EPTB specimens that were processed by conventional culture on Lowenstein–Jensen (LJ) medium and the rapid molecular-based GeneXpert MTB/RIF assay system. Results: Among the 287 EPTB samples tested, GeneXpert detected the deoxyribonucleic acid of MTBC in 51 samples (17.8%). Standard bacteriological assays, including acid-fast bacilli microscopy and culture, were positive in 26 (9.1%) and 35 (12.1%) specimens respectively. The performance of GeneXpert results was evaluated against culture as a gold standard. The overall sensitivity and specificity of the Xpert assay were calculated to be 94.6 and 94.4%, respectively. The sensitivity of the Xpert assay with tissue specimens was 84.6 and 80.7% specificity, while there was 86.6% sensitivity and 98.1% specificity with the body fluids. Conclusion: GeneXpert had high performance than culture for the EPTB specimen. It can be a useful tool for the early diagnosis of patients with high clinical suspicion of EPTB. The other major advantage of GeneXpert is that it simultaneously detects rifampicin resistance within 2 hours.

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