MTB detection frequency using GeneXpert MTB/RIF ultra assay on pleural tissue in the evaluation of exudative lymphocytic effusion
DOI:
https://doi.org/10.61529/idjp.v35i2.565Abstract
Background: Pleural tuberculosis is a paucibacillary disease, which makes the diagnosis of tuberculous pleural effusion particularly challenging. The study aimed to establish the accuracy of GeneXpert MTB / RIF Ultra in the diagnosis of Mycobacterium tuberculosis in pleural biopsy samples.
Material and Methods: It was a cross-sectional observational study, done at the Department of Pulmonology, Ojha Institute of Chest Disease, Dow University of Health Sciences, Karachi, following institutional ethical approval. Adult patients with exudative lymphocytic pleural effusion were enrolled by consecutive sampling. Biopsy samples of pleura have been collected through medical thoracoscopy or image-guided methods and examined using GeneXpert MTB/RIF Ultra. The data had been analyzed with SPSS version 25, and effect modifiers were stratified; p < 0.05 was regarded as significant.
Results: A total of 130 patients were evaluated. Mean age was 47.3 ± 16.8 years. In 88 (67.7%) patients, histopathological findings were suggestive of tuberculosis. GeneXpert MTB/RIF Ultra assay showed a sensitivity of 36.4%, specificity of 90.5%, PPV of 88.9% and NPV of 40.4%. Stratification analysis revealed significant correlations of GeneXpert positivity with age (p = 0.041), effusion laterality (p = 0.028) and lymphocyte predominance (p = 0.019).
Conclusion: GeneXpert MTB/RIF Ultra has high specificity and low sensitivity in pleural biopsy samples. The high positive predictive value of tuberculous pleura however, justifies its use as a confirmatory test in suspected tuberculous pleural effusion.
Keywords: Biopsy, Molecular diagnostic techniques, Pleural, Pleural effusion, Tuberculosis
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