The utility of Xpert MTB/RIF in the diagnosis of Tubercular Mediastinal Lymphadenopathy by Endobronchial Ultrasound – R. Gupta, A. Bhatia, S. Joshi, N. Tayal, P. Pandey, A. Gupta, European Respiratory Journal Sep2019, 54 (suppl 63) PA2988

Post Date: November 24, 2021

Background: We aim to evaluate the performance of Xpert MTB/RIF in Endobronchial Ultrasound guided needle aspiration (EBUS-TBNA) samples for rapid diagnosis of Tubercular Mediastinal Lymphadenopathy.

Methods: A retrospective analysis of patients with Mediastinal lymphadenopathy who underwent EBUS-guided TBNA and were diagnosed as Tuberculosis (TB) was done in the study period. The performance of a Xpert MTB/RIF assay on the TBNA samples was evaluated against standard diagnostic tests, microscopy and culture diagnosed Tuberculosis.

Results: Among 79 benign lymph node samples, 34 patients were microbiologically diagnosed with Tuberculosis. Eight cases with negative smear and cultures were given a probable diagnosis of Tuberculosis on the basis of caseating granulomatous inflammation on histopathology. A single Xpert MTB/RIF assay demonstrated overall sensitivity for culture-positive Tuberculosis of 42% and specificity of 100%. Four lymph node samples had microbiological culture positivity and Xpert MTB/RIF assay as a diagnostic feature. It decreased the median time to diagnosis and starting treatment based on the Xpert MTB/RIF assay. The median time to diagnosis using Xpert MTB/RIF (1 day) was two days shorter than conventional Histopathology methods (3 days). Rifampicin resistance was not detected in any patients.

Conclusions: Xpert MTB/RIF using EBUS-TBNA samples is a useful laboratory test with good specificity in the diagnosis of tuberculosis. In high prevalence countries of Tuberculosis, Xpert MTB/RIF can decrease the diagnosis and treatment initiation time when combined with the conventional microscopy and histopathology