Diagnostic value of Xpert MTB/RIF assay on pleural tissue obtained via closed pleural biopsy among persons with presumptive tuberculous pleuritis

BACKGROUND: Tuberculous pleuritis (TBP) is a common extrapulmonary tuberculosis that contributes to the tuberculosis burden. Xpert MTB/RIF assay is a promising method for rapid diagnosis of TBP. The diagnostic value of Xpert MTB/RIF assay in pleural tissue obtained via closed pleural biopsy among sputum acid-fast bacilli (AFB) smear-negative persons is not well studied. OBJECTIVES: To evaluate the diagnostic value of Xpert MTB/RIF assay on diagnosis of TB in pleural tissue obtained via blind closed pleural biopsy. METHODS: Closed pleural biopsy using Cope needle was performed on adult patients who presented with lymphocyte predominant exudative pleural effusion. Xpert MTB/RIF assay was performed in parallel to pathology and mycobacterial culture of the pleural tissue specimen to determine its sensitivity and specificity. Final clinical diagnosis of TBP was determined by improvement in 2-months follow-up of anti-tuberculous treatment. RESULTS: A total of 33 patients were included in the study. The median (interquartile range (IQR)) age was 27 (25 - 42) years. The sensitivity and specificity of Xpert MTB/RIF assay was 30% and 100% compared with Mycobacterium tuberculosis culture as the gold standard, and 20% and 95.7% compared with histopathology as the gold standard. CONCLUSION: Xpert MTB/RIF assay in pleural tissue obtained by closed pleural biopsy did not increase diagnostic yield, but it shortens time for diagnosis compared with conventional methods.