Publication date: Jul 29, 2026
An important step towards Tuberculosis elimination is rapid identification of extrapulmonary tuberculosis (EPTB) cases and universal drug-susceptibility testing (DST). This study evaluated the performance of Xpert(R) MTB/XDR assay in detecting drug-resistant EPTB and compared its performance with phenotypic and genotypic DST. 62 samples diagnosed as EPTB by Xpert(R) MTB/RIF Ultra were subjected to Xpert(R) MTB/XDR assay (Xpert(R)-XDR), phenotypic DST using mycobacterial growth indicator tube and genotypic DST using line probe assay (LPA). Gene sequencing was done to settle discordant results. Tests were compared using categorial agreement (CA), very major error (VME) and major error (ME). 57 cases having Ct values between 15-22 in Xpert(R) MTB/RIF Ultra were detected by Xpert(R)-XDR. 100% concordance was noted between Xpert(R)-XDR and phenotypic & genotypic DST in reporting susceptibility against isoniazid and second-line injectables. Three cases and one case of false-resistance were reported against phenotypic and genotypic DST, respectively. Categorical agreement was 98. 8% against phenotypic DST and 99. 6% against genotypic DST. There were no VMEs and MEs were within acceptable range. Xpert(R)-XDR can be used as a reflex test following EPTB detection (e. g., by Xpert(R)-Ultra) to direct early and successful therapy in settings with high TB and DR-TB burden.
| Concepts | Keywords |
|---|---|
| molecular diagnosis | |
| sequencing | |
| XDR-TB |
Semantics
| Type | Source | Name |
|---|---|---|
| disease | MESH | Extrapulmonary tuberculosis |
| disease | MESH | Tuberculosis |
| pathway | KEGG | Tuberculosis |
| drug | DRUGBANK | Dihydrostreptomycin |
| drug | DRUGBANK | Isoniazid |
| disease | MESH | MEs |
| disease | MESH | XDR-TB |