Rapid diagnosis of pleural tuberculosis by Xpert MTB/RIF assay using pleural biopsy and pleural fluid specimens.

Abstract

BACKGROUND:

Early pleural tuberculosis (TB) diagnosis is particularly difficult. The aim of this study was to investigate the diagnostic accuracy of the Xpert MTB/RIF (Xpert) (Cepheid, Sunnyvale, CA) assay using pleural biopsy and pleural fluid specimens in patients with suspected pleural TB but who had a negative sputum acid-fast bacilli (AFB) smear.

MATERIALS AND METHODS:

In this study, 134 sputum smear-negative suspected pleural TB patients were selected. Paired pleural fluid and pleural biopsy specimens were tested for Mycobacterium tuberculosis by standard smear-microscopy, Lowenstein-Jensen and mycobacterial growth indicator tube (MGIT) culture, and the Xpert assay. Mycobacterial culture from pleural biopsy specimens was used as a reference standard for sensitivity and specificity calculations. Detection of rifampicin resistance was compared with the MGIT method.

RESULTS:

Of 126 evaluable patients, 55 received a diagnosis of pleural TB. The sensitivity of the Xpert assay using pleural biopsy specimens for the diagnosis of pleural TB was 85.5%, and specificity was 97.2%. The sensitivity and specificity of the Xpert assay in pleural fluid were 43.6% and 98.6%, respectively. The Xpert assay correctly identified 90.0% of phenotypic rifampicin-resistant cases and 93.9% of phenotypic rifampicin-susceptible cases.

CONCLUSION:

The Xpert assay on pleural biopsy specimens may provide an accurate diagnosis of pleural TB in patients who had a negative AFB smear.

• Authors: Jinghui Du, Zikun Huang, Qing Luo, Guoliang Xiong, Xiaomeng Xu, Weiting Li, Xu Liu, Junming Li
• Journal: Journal of research in medical sciences : the official journal of Isfahan University of Medical Sciences (J Res Med Sci) Vol. 20 Issue 1 Pg. 26-31 (Jan 2015) ISSN: 1735-1995 [Print] India
• PMID: 25767518 (Publication Type: Journal Article)