Xpert MTB/RIF Ultra as a diagnostic tool for pleural tuberculosis: a study at Indian tertiary care centre

Despite the advent of Xpert MTB/RIF, pleural tuberculosis (TB) diagnosis in pleural fluid is still difficult. Hence, we assessed the diagnostic efficacy of its advanced version, Xpert MTB/RIF Ultra, for pleural TB diagnosis using pleural fluid as a sample. Tuberculosis pleuritis (TBP) suspects (n = 261) were enrolled in the study, of which 29 were excluded. The remaining patients (n = 232) were categorized into definite TBP (n = 31), probable TBP (n = 28), and non-TB controls (n = 173) based on the composite reference standard consisting of smear, culture, histopathology, and Xpert MTB/RIF as well as follow-up/clinical response to anti-TB therapy. Among the TBP suspects, 59 were diagnosed as TBP patients. The sensitivity of Xpert MTB/RIF Ultra (52.5%) using pleural fluid for TBP diagnosis was higher than sensitivity obtained with smear (22.4%), culture (17.6%), and Xpert MTB/RIF (25%) alone, carried out using either pleural fluid or pleural biopsy or both the samples. In cases of probable TBP, where none of the laboratory tests were positive, Xpert MTB/RIF Ultra use led to an increased diagnostic percentage of definite TBP from 52.5% to 69.4%. Overall, Xpert MTB/RIF Ultra showed promising results for a definitive diagnosis of TBP in pleural fluid samples.