A verification and EQA program specific to the GeneXpert has been developed based on Dried Culture Spots (DCS). The program is based on inactivated MGIT positive cultures which are quantitated using a specially developed flow cytometry protocol and then spotted onto Whatman 903 perforated paper cards. After drying, the spots can be individually cut, processed and tested on the Xpert MTB/RIF assay as per the normal Xpert protocol.
For the verification program, the DCS will be tested on each module of the Xpert instrument after installation at sites, to ensure that the modules are fit for result reporting. For the EQA program, batches of spots will be tested on instruments at varying times throughout the year to ensure the continual quality of testing and result reporting.