Performance of Gene Xpert MTB/RIF® in the diagnosis of extrapulmonary tuberculosis in Dakar: 2010-2015

The challenge facing developing countries is the availability of methods for rapid and accurate diagnosis of tuberculosis. So me mo lecular techniques offer this advantage, so we used GeneXpert MTB / RIF test in the diagnosis of extra - pulmonary tuberculosis to evaluate its performance compared with conventional methods. Methods: between 2010 and 2015, 544 extrapulmonary clinical specim ens were collected and analyzed by microscopy, culture and GeneXpert. The evaluation of antitubercular susceptibility testing was performed using th e MGIT 960 system. Genotype MTBDRplus was used to confirm the cases of rifampicin resistance detected by the GX system. Results: the study population included 544 patients, 55.15% men and 44.85% women. Patients age ranged from 1 - 92 years with the majority in the 18 - 45 age group. The sensitivity and the overall specificity of microscopy was 43.86% and 98.36%, 94. 74% and 97.95% for GeneXpert® respectively (95% CI). There were two discrepant rifampicin - resistant results between GeneXpert test and phenotypic method. Among these cases MTBDRplus test results showed 100% agreement with those of the MGIT 960. Conclusion: this study shows that the GeneXpert test exhibits high sensitivity for routine diagnosis of extra - pulmonary tuberculosis and should be used instead of microscopy. The cases of rifampicin resistance detected by GeneXpert sho uld be confirmed by other molecu lar testing methods before initiating treatment. (Authors)