Comparison of the CapitalBio™ Mycobacterium RT-PCR detection test and Xpert MTB/RIF assay for diagnosis of renal tuberculosis

The purpose of this study is to compare the efficiency difference between CapitalBio™ Mycobacterium real-time polymerase chain reaction (RT-PCR) detection test and Xpert MTB/RIF assay for the diagnosis of renal tuberculosis (TB). We analyzed 117 samples collected between July 1, 2018, and October 31, 2019, from patients with suspected renal TB to determine the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of the CapitalBio™ Mycobacterium RT-PCR detection test for renal TB and to evaluate its diagnostic accuracy compared with Xpert MTB/RIF assay. Five cases were excluded from this study because of incomplete data. Taking clinical diagnosis as the gold standard, for the Xpert MTB/RIF assay, the sensitivity was 87.95% (78.96–94.07%), specificity 96.55% (82.24–99.91%), PPV 98.65% (92.70–99.97%), NPV 73.68% (56.90–86.60%), and AUC 0.92 (0.86–0.96). For the CapitalBio™ Mycobacterium RT-PCR detection test, the overall sensitivity was 84.34% (74.71–91.39%), specificity 93.10% (77.23–99.15%), PPV 97.22% (90.32–99.66%), NPV 67.50% (50.87–81.43%), and AUC 0.89(0.81–0.94). The diagnostic efficiency of the CapitalBio™ Mycobacterium RT-PCR detection test was similar to that of the Xpert MTB/RIF assay in patients with renal TB. Hence, the CapitalBio™ Mycobacterium RT-PCR detection test presents a valuable alternative for the diagnosis of renal TB.