Efficacy of the Xpert Mycobacterium tuberculosis/rifampicin assay for diagnosing sputum-smear negative or sputum-scarce pulmonary tuberculosis in bronchoalveolar lavage fluid

ObjectiveTo evaluate he diagnostic performance of the Xpert Mycobacterium tuberculosis/Rifampin (MTB/RIF) assay in bronchoalveolar lavage fluid (BALF).MethodsWe retrospectively reviewed clinical data from 671 sputum-smear negative or sputum-scarce adult patients with suspected pulmonary tuberculosis (PTB) who had an MTB/RIF performed on BALF. The assay, smear microscopy (SM) and MTB culture was evaluated using final diagnosis as reference standard.ResultsCompared culture, sensitivity specificity were 87.8% 72.7% for 11.0% 99.2% SM, respectively. Compared diagnosis, 58.9% 83.9% 5.0% 98.3% 43.3% 100% low high sensitivity. When very results re-evaluated considered MTB-negative, increased significantly. remained higher than SM similar to that culture.ConclusionsThe adds microbiologic evidence decisions; however, close attention should be paid semi-quantitative positive results.