The utility of Xpert MTB/RIF performed on bronchial washings obtained in patients with suspected pulmonary tuberculosis in a high prevalence setting
Date
2015-09-16
Journal Title
Journal ISSN
Volume Title
Publisher
BioMed Central
Abstract
Background: Xpert MTB/RIF has been shown to have a superior sensitivity to microscopy for acid fast bacilli (AFB)
in sputum and has been recommended as a standard first line investigation for pulmonary tuberculosis (PTB).
Bronchoscopy is a valuable tool in diagnosing PTB in sputum negative patients. There is limited data on the utility
of Xpert MTB/RIF performed on bronchial lavage specimens. Our aim was to evaluate the diagnostic efficiency of
Xpert MTB/RIF performed on bronchial washings in sputum scarce/negative patients with suspected PTB.
Methods: All patients with a clinical and radiological suspicion of PTB who underwent bronchoscopy between
January 2013 and April 2014 were included. The diagnostic efficiencies of Xpert MTB/RIF and microscopy for AFB
were compared to culture for Mycobacterium tuberculosis.
Results: Thirty nine of 112 patients were diagnosed with culture-positive PTB. Xpert MTB/RIF was positive in 36/39
with
a sensitivity of 92.3 % (95 % CI 78–98 %) for PTB, which was superior to that of smear microscopy (41 %; 95 % CI
26.0–57.8 %, p = 0.005). The specificities of Xpert MTB/RIF and smear microscopy were 87.7 % (95 % CI 77.4–93.9 %)
and 98.6 % (95 % CI 91.6 %–99.9 %) respectively. Xpert MTB/RIF had a positive predictive value of 80 % (95 % CI;
65–89.9 %) and negative predictive value of 95.5 % (95 % CI 86.6–98.8 %). 3/9 patients with Xpert MTB/RIF positive
culture negative results were treated for PTB based on clinical and radiological findings.
Conclusion: Xpert MTB/RIF has a higher sensitivity than smear microscopy and similar specificity for the immediate
confirmation of PTB in specimens obtained by bronchial washing, and should be utilised in patients with a high
suspicion of pulmonary tuberculosis.
Description
CITATION: Barnard, D. A. et al. 2015. The utility of Xpert MTB/RIF performed on bronchial washings obtained in patients with suspected pulmonary tuberculosis in a high prevalence setting. BMC Pulmonary Medicine, 15:103, doi:10.1186/s12890-015-0086-z.
The original publication is available at http://bmcpulmmed.biomedcentral.com
The original publication is available at http://bmcpulmmed.biomedcentral.com
Keywords
Pulmonary tuberculosis -- Treatment, Mycobacterium tuberculosis, pulmonary tuberculosis -- Diagnosis, Xpert MTB/RIF
Citation
Barnard, D. A. et al. 2015. The utility of Xpert MTB/RIF performed on bronchial washings obtained in patients with suspected pulmonary tuberculosis in a high prevalence setting. BMC Pulmonary Medicine, 15:103, doi:10.1186/s12890-015-0086-z.