Comparison between the diagnostic accuracy of Xpert MTB/Rif assay and culture for pleural tuberculosis using tissue biopsy

Abstract

BackgroundEarly diagnosis of pleural tuberculosis is difficult as it is a paucibacillary disease and a combination of tests is required to diagnose it, which have varied diagnostic accuracy and increase the cost. The aim of this study was to evaluate the diagnostic performance of the Xpert MTB/Rif assay on thoracoscopic pleural biopsy specimens.MethodsA total of 201 patients with exudative pleural effusion and normal lung parenchyma were included in the study. All patients underwent thoracoscopic pleural biopsy under local anaesthesia. Biopsy samples were sent for Xpert MTB/Rif assay and culture, along with histopathology. Chronic granulomatous inflammation on histopathology and response to antituberculous treatment was taken as the reference standard for diagnosis of tuberculous pleurisy.ResultsOf the 198 patients included in the final analysis, 134 had pleural tuberculosis. The sensitivity of the Xpert assay was 52.2% and specificity was 100%, and that of pleural biopsy cultures were 41% and 100% respectively.ConclusionThe sensitivity and specificity of Xpert MTB/Rif assay scores were high, hence escalating the speed of diagnosis and imparting marked impact on patient outcomes. The Xpert MTB/Rif assay is a potential game changer in diagnosing pleural tuberculosis.

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

“…The reported sensitivity of PCR is highly heterogeneous, ranging between 45% and 100%, depending on the method of PCR assay, gold standards and method of biopsy. [9 - 11 , 20 - 22] The conventional PCR studies [20 – 22] reported higher sensitivity (56 - 100%) than the Xpert MTB/RIF assay studies (30 - 85%). [9 – 11] Most studies obtained pleural tissue by either computed tomography-guided biopsy [22] or thoracoscopic biopsy.…”

“…[9 - 11 , 20 - 22] The conventional PCR studies [20 – 22] reported higher sensitivity (56 - 100%) than the Xpert MTB/RIF assay studies (30 - 85%). [9 – 11] Most studies obtained pleural tissue by either computed tomography-guided biopsy [22] or thoracoscopic biopsy. [10 , 11 , 20] Only one study obtained pleural tissue via closed pleural biopsy.…”

“…[9 – 11] Most studies obtained pleural tissue by either computed tomography-guided biopsy [22] or thoracoscopic biopsy. [10 , 11 , 20] Only one study obtained pleural tissue via closed pleural biopsy. [21] The closed pleural biopsy study used conventional PCR and its sensitivity was 90%, [21] which is much higher than our results.…”

“…This finding is consistent with other studies that used tissue pathology as the gold standard and reported a sensitivity of 45 - 52.2%. [10 , 11] The studies that used M. tuberculosis culture as the gold standard reported sensitivity in the range of 85 - 100%. [9 , 20 , 21] It is unclear why the sensitivity of the PCR assay is higher when using M. tuberculosis culture as the gold standard than when using tissue pathology as the gold standard.…”

Etiological Distribution and Morphological Patterns of Granulomatous Pleurisy in a Tuberculosis-prevalent Country

“…Definite discrimination between these 2 etiologies can be established only by PCR and culture. 11 12 Two patients with NTM granulomatous pleurisy were diagnosed by positive NTM culture in pleural tissue or fluid. These findings indicate that clinicians should actively make every effort to find microbiological evidence of potential pathogens in all available specimens, even in cases with granulomatous histological results.…”