Diagnosis of tuberculous pleural effusion in a tertiary care hospital of central India: The role of xpert Mycobacterium tuberculosis/rifampicin

Background: In India, 15%-20% of tuberculosis (TB) cases are categorized as extra-pulmonary TB, and tuberculous pleural effusion (TPE) is the second-most common type after tuberculous lymphadenitis. However, the paucibacillary nature of TPE makes its diagnosis challenging. As a result, relying on empirical anti-TB treatment (ATT) based on clinical diagnosis becomes necessary for achieving the best possible diagnostic outcome. The study aims to determine the diagnostic utility of Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) for the detection of TB in TPE in high incidence setting of Central India. Methods: The study enrolled 321 patients who had exudative pleural effusion detected through radiological testing and were suspected of having TB. The medical procedure of thoracentesis was conducted to collect the pleural fluid, which was then subjected to both the Ziehl-Neelsen staining and Xpert MTB/RIF test. The patients who showed improvement after receiving anti-Tuberculosis treatment (ATT) were considered the composite reference standard. Results: The sensitivity of smear microscopy was found to be 10.19%, while that of the Xpert MTB/RIF method was 25.93% when compared to the composite reference standard. The accuracy of clinical diagnosis was measured using receiver operating characteristics based on clinical symptoms, and it was found to be 0.858 (area under the curve). Conclusions: The study shows that Xpert MTB/RIF has significant value in diagnosing TPE, despite its low sensitivity of 25.93%. Clinical diagnosis based on symptoms was relatively accurate, but relying on symptoms alone is not enough. Using multiple diagnostic tools, including Xpert MTB/RIF, is crucial for accurate diagnosis. Xpert MTB/RIF has excellent specificity and can detect RIF resistance. Its quick results make it useful in situations where a rapid diagnosis is necessary. While it should not be the only diagnostic tool, it has a valuable role in diagnosing TPE.