Bankar S, Set R, Sharma D, Shah D, Shastri J. Diagnostic accuracy of Xpert MTB/RIF assay in extrapulmonary tuberculosis.
Indian J Med Microbiol 2019;
36:357-363. [PMID:
30429387 DOI:
10.4103/ijmm.ijmm_18_173]
[Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Introduction
The WHO endorsed Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) assay, has been evaluated for pulmonary TB in a number of studies but very few have investigated it for extrapulmonary specimens. The present study evaluates the performance of Xpert MTB/RIF assay in the diagnosis of extrapulmonary TB (EPTB).
Aim and Objectives
The aim of the study is to determine sensitivity and specificity of Xpert MTB/RIF assay for diagnosis of EPTB and RIF resistance in comparison to culture on Lowenstein-Jensen (LJ) medium and proportion method (PM), respectively.
Materials and Methods
A total of 738 specimens from clinically suspected cases of EPTB were subjected to Ziehl-Neelsen staining, Xpert MTB/RIF assay and culture on LJ medium. PM was done on MTB isolates.
Results
The sensitivity, specificity of Xpert MTB/RIF assay for diagnosis of EPTB were 84.91% (95% confidence interval [CI] 72.41%-93.25%) and 86.72% (95% CI 83.94%-89.17%) and for RIF resistance detection were 60.00% (95% CI 32.29%-83.66%) and 94.74% (95% CI 73.97%-99.87%), respectively. Among culture-positive cases, the sensitivity of Xpert MTB/RIF assay was 94.12% in smear positive and 80.56% in smear-negative cases. Xpert MTB/RIF showed maximum sensitivity of MTB detection from lymph node specimens (100% [95% CI 54.07%-100.00%]) and other body fluids (100% [95% CI 15.81%-100.00%]).
Conclusion
The present study establishes Xpert MTB/RIF assay as a promising tool in the rapid diagnosis of EPTB and detection of RIF resistance.
Collapse