Efficacy and role of Xpert® Mycobacterium tuberculosis/rifampicin assay in urinary tuberculosis

Introduction: The aim was to study the accuracy of Xpert® (Cepheid Inc., Sunnyvale, CA, USA) Mycobacterium tuberculosis/rifampicin (MTB/RIF) assay as compared to a composite gold standard (urine culture, imaging, and biopsy) and to asses its utility as the initial test compared to smear microscopy t...

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Main Authors: Benedict Paul Samuel, Joy Sarojini Michael, J Chandrasingh, Santosh Kumar, Antony Devasia, Nitin Sudhakar Kekre
Format: Article
Language:English
Published: Wolters Kluwer Medknow Publications 2018-01-01
Series:Indian Journal of Urology
Online Access:http://www.indianjurol.com/article.asp?issn=0970-1591;year=2018;volume=34;issue=4;spage=268;epage=272;aulast=Samuel
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spelling doaj-a4f498e63d6f44999e228c499f0d30c92020-11-25T00:33:40ZengWolters Kluwer Medknow PublicationsIndian Journal of Urology0970-15911998-38242018-01-0134426827210.4103/iju.IJU_189_18Efficacy and role of Xpert® Mycobacterium tuberculosis/rifampicin assay in urinary tuberculosisBenedict Paul SamuelJoy Sarojini MichaelJ ChandrasinghSantosh KumarAntony DevasiaNitin Sudhakar KekreIntroduction: The aim was to study the accuracy of Xpert® (Cepheid Inc., Sunnyvale, CA, USA) Mycobacterium tuberculosis/rifampicin (MTB/RIF) assay as compared to a composite gold standard (urine culture, imaging, and biopsy) and to asses its utility as the initial test compared to smear microscopy to diagnose urinary tuberculosis. Methods: This prospective study included adult patients suspected to have urinary tuberculosis from March 2014 to December 2017. Three urine samples were collected from each patient and were subjected to Xpert MTB/RIF assay, acid-fast bacillus (AFB) smear microscopy, and liquid media (BACTEC Mycobacteria Growth Indicator Tube [MGIT] 960) culture. Imaging and tissue biopsies were performed as clinically indicated. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated using the bootstrap method for 95% confidence intervals for the Xpert assay. Results: Xpert MTB/RIF assay was found to be superior to the currently best available light-emitting diode fluorescent smear microscopy as the initial test for urinary tuberculosis (sensitivity of 69.09% vs. 32.72%). The Xpert MTB/RIF polymerase chain reaction test was found to have a moderate sensitivity (69.09%) and high specificity (100%) as compared to the composite reference standard. The sensitivity of liquid AFB culture MGIT 960 as compared to the reference standard was 90.32%. Conclusions: Xpert MTB/RIF assay on an early morning first void urine specimen can replace smear microscopy as the initial diagnostic test for urinary tuberculosis.http://www.indianjurol.com/article.asp?issn=0970-1591;year=2018;volume=34;issue=4;spage=268;epage=272;aulast=Samuel
collection DOAJ
language English
format Article
sources DOAJ
author Benedict Paul Samuel
Joy Sarojini Michael
J Chandrasingh
Santosh Kumar
Antony Devasia
Nitin Sudhakar Kekre
spellingShingle Benedict Paul Samuel
Joy Sarojini Michael
J Chandrasingh
Santosh Kumar
Antony Devasia
Nitin Sudhakar Kekre
Efficacy and role of Xpert® Mycobacterium tuberculosis/rifampicin assay in urinary tuberculosis
Indian Journal of Urology
author_facet Benedict Paul Samuel
Joy Sarojini Michael
J Chandrasingh
Santosh Kumar
Antony Devasia
Nitin Sudhakar Kekre
author_sort Benedict Paul Samuel
title Efficacy and role of Xpert® Mycobacterium tuberculosis/rifampicin assay in urinary tuberculosis
title_short Efficacy and role of Xpert® Mycobacterium tuberculosis/rifampicin assay in urinary tuberculosis
title_full Efficacy and role of Xpert® Mycobacterium tuberculosis/rifampicin assay in urinary tuberculosis
title_fullStr Efficacy and role of Xpert® Mycobacterium tuberculosis/rifampicin assay in urinary tuberculosis
title_full_unstemmed Efficacy and role of Xpert® Mycobacterium tuberculosis/rifampicin assay in urinary tuberculosis
title_sort efficacy and role of xpert® mycobacterium tuberculosis/rifampicin assay in urinary tuberculosis
publisher Wolters Kluwer Medknow Publications
series Indian Journal of Urology
issn 0970-1591
1998-3824
publishDate 2018-01-01
description Introduction: The aim was to study the accuracy of Xpert® (Cepheid Inc., Sunnyvale, CA, USA) Mycobacterium tuberculosis/rifampicin (MTB/RIF) assay as compared to a composite gold standard (urine culture, imaging, and biopsy) and to asses its utility as the initial test compared to smear microscopy to diagnose urinary tuberculosis. Methods: This prospective study included adult patients suspected to have urinary tuberculosis from March 2014 to December 2017. Three urine samples were collected from each patient and were subjected to Xpert MTB/RIF assay, acid-fast bacillus (AFB) smear microscopy, and liquid media (BACTEC Mycobacteria Growth Indicator Tube [MGIT] 960) culture. Imaging and tissue biopsies were performed as clinically indicated. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated using the bootstrap method for 95% confidence intervals for the Xpert assay. Results: Xpert MTB/RIF assay was found to be superior to the currently best available light-emitting diode fluorescent smear microscopy as the initial test for urinary tuberculosis (sensitivity of 69.09% vs. 32.72%). The Xpert MTB/RIF polymerase chain reaction test was found to have a moderate sensitivity (69.09%) and high specificity (100%) as compared to the composite reference standard. The sensitivity of liquid AFB culture MGIT 960 as compared to the reference standard was 90.32%. Conclusions: Xpert MTB/RIF assay on an early morning first void urine specimen can replace smear microscopy as the initial diagnostic test for urinary tuberculosis.
url http://www.indianjurol.com/article.asp?issn=0970-1591;year=2018;volume=34;issue=4;spage=268;epage=272;aulast=Samuel
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