Abstract
Background: Xpert MTB/Rif has been shown to have a superior sensitivity to microscopy for acid fast bacilli (AFB) in sputum and is recommended as a point-of-care test. Bronchoscopy is a valuable tool in diagnosing pulmonary tuberculosis (TB) in sputum negative patients. There is limited data on the utility of Xpert MTB/Rif performed on bronchial lavages.
Aim: To evaluate the diagnostic efficiency of Xpert MTB/Rif performed on bronchial lavage in sputum scarce or sputum negative patients with suspected pulmonary TB.
Methods: All patients with a clinical and radiological suspicion of pulmonary TB who underwent bronchoscopy between January 2013 and April 2014 were included. The diagnostic efficiency of Xpert MTB/Rif, microscopy for AFB and culture for Mycobacterium tuberculosis were evaluated.
Results: 42 of 112 patients were diagnosed with confirmed pulmonary TB; 39 were culture positive and Xpert MTB/Rif was positive in 37 of 42. Xpert MTB/RIF had a sensitivity of 88.1% (95%CI; 73.6-95.5%) for TB, which was superior to that of smear microscopy (38.1%; 95%CI; 24.0-54.3, p=0.005). The specificity of Xpert MTB/Rif was comparable to smear microscopy (88.6%; 95%CI; 78.2-94.6 vs. 98.6%; 95%CI; 91.2-99.9). Xpert MTB/Rif had a positive predictive value of 82.2% (95%CI; 67.4-91.5) and negative predictive value of 92.5% (95%CI; 82.7-97.2). Eight false positive Xpert MTB/RIF cases were identified.
Conclusion: Xpert MTB/RIF has a higher sensitivity than smear microscopy and similar specificity for the immediate confirmation of pulmonary TB in specimens obtained by bronchial lavage, and should be utilised in patients with a high clinical suspicion of pulmonary tuberculosis.
- Copyright ©ERS 2015