The application of Xpert MTB/RIF assay for rapid diagnosis of osteoarticular tuberculosis

English Keywords:Xpert MTB/RIF  Osteoarticular tuberculosis  Rapid diagnosis

English Abstract:

  【Abstract】 Objectives: To investigate the role of Xpert MTB/RIF assay for rapid diagnosis of osteoarticular tuberculosis. Methods: From February 2014 to November 2014, pus specimens of 49 osteoarticular tuberculosis patients and 32 nontuberculosis patients were detected by Xpert MTB/RIF system, and the sensitivity, specificity, positive predictive value, negative predictive value, agreement rate of Xpert MTB/RIF system were calculated, and clinical diagnosis was used as the reference standard. All the pus specimens were detected by acid-fast stain and fast culturing(BACTECT MGIT 960), to find the difference of sensitivity and specificity among Xpert MTB/RIF, acid-fast stain, and fast culturing. The role of Xpert MTB/RIF assay for rapid diagnosis of osteoarticular tuberculosis was evaluated through the two factors above. Results: It took 2.3±0.2h to detect each pus specimen by Xpert MTB/RIF. Among the 49 osteoarticular disease patients, 46 were positive, 3 were negative by Xpert MTB/RIF test. Among the 32 nontuberculosis patients, 1 was positive, 31 were negative by Xpert MTB/RIF test. The sensitivity, specificity, positive predictive value, negative predictive value, agreement rate was 93.87%, 96.87%, 97.87%, 91.17%, 95.06% respectively for Xpert MTB/RIF assay. Among the 46 specimens which were positive by Xpert MTB/RIF test, 10 had rifampicin resistance mutation, with the rate of rifampicin resistance mutation as 21.73%. Among the 49 osteoarticular disease patients, 8 were positive, 41 were negative by acid-fast stain test, the sensitivity was 17.39%, and based on fast culturing test, 11 were positive, 38 were negative, the sensitivity was 23.91%. All pus specimens of 32 nontuberculosis patients were negative by acid-fast stain test and fast culturing test. As for the sensitivity, Xpert MTB/RIF was superior to acid-fast stain and fast cultureing（P<0.05）. While as for the specificity, there was no statistical difference among Xpert MTB/RIF, acid-fast stain, or fast culturing（P>0.05）. Conclusions: The role of Xpert MTB/RIF assay for rapid diagnosis of osteoarticular tuberculosis is perfect. It is of time saving, high sensitivity and high specificity, which is superior to the traditional methods.