Xpert MTB/RIF Ultra enhanced tuberculous pleurisy diagnosis for patients with unexplained exudative pleural effusion who underwent a pleural biopsy via thoracoscopy: A prospective cohort study

Abstract

Introduction: To evaluate the performance of Xpert MTB/RIF Ultra (Xpert-Ultra) in testing pleural tissue and fluid collected by medical thoracoscopy among patients with unexplained exudative pleural effusion.

Methods: Patients with an undiagnosed exudative pleural effusion were prospectively and consecutively recruited. Pleural tissue and fluid were collected by medical thoracoscopy and subjected to culture, Xpert MTB/RIF (Xpert) and Xpert-Ultra assays. Histopathological examination was also performed with the tissue and used as the major reference.

Results: Sixty-one patients were enrolled, including: 27 tuberculosis (TB) pleurisy, 15 malignancy and 19 other chronic infection cases. The sensitivity, specificity, positive predictive value, and negative predictive value of Xpert-Ultra for TB diagnosis were 85.19% (23/27), 97.06% (33/34), 95.83% (23/24), and 89.19% (33/37), respectively. Xpert-Ultra testing with the biopsy tissue alone had an equivalent diagnostic capacity to that of pathological examination for the diagnosis of confirmed TB cases. By combining the pathological examination with Xpert-Ultra for biopsy, the percentage of confirmed TB cases greatly increased (i.e. 92.59% (25/27)). The "trace" positive outcome of Xpert-Ultra was highly supportive of TB diagnosis for both biopsy tissue and pleural fluid examinations.

Conclusion: With the specimens collected by medical thoracoscopy, the Xpert-Ultra assay presented high value in identifying TB among pleurisy patients who had difficulties in etiological diagnosis.

Keywords: Medical thoracoscopy; Tuberculosis; Unexplained exudative pleural effusion; Xpert MTB/RIF Ultra.