Assessing the diagnostic accuracy of the Xpert MTB/RIF assay in detecting epididymal tuberculosis.

Abstract

We analyzed 84 samples from patients with suspected epididymal TB or chronic epididymitis who received surgical treatment (epididymal resection or epididymis-testicular resection) at our hospital between July 1, 2016 and July 1, 2020. A composite reference standard (CRS) was used in this study. We determined the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of the Xpert MTB/RIF assay for epididymal TB and compared its diagnostic accuracy with that of the Mycobacterium tuberculosis (MTB) culture test in detecting epididymal TB. Three patients were excluded because of incomplete data. Comparing with the composite reference standard, the sensitivity, specificity, PPV, NPV, and AUC of Xpert MTB/RIF assay for epididymal TB were 80.95% (69.09-89.75%); 94.44% (72.71-99.86%); 98.08% (89.74-99.95%); and 58.62% (38.94-76.48%), respectively, with an AUC of 0.88 (95% confidence interval: 0.79-0.94). The diagnostic sensitivity of the Xpert MTB/RIF assay was significantly higher than that of the MTB culture test for epididymal TB. We recommend the Xpert MTB/RIF assay as a diagnostic method for the detection of epididymal TB.