GeneXpert Robol Cartridge The cartridge is made up of four distinct parts. The cartridge body, the valve body, the foot, and the lid. Let's investigate how the GeneXpert cartridge works. First, pipette your sample into the sample area of the cartridge. After that is done, you close the cap and place the cartridge into an empty bay in the instrument. When the instrument begins, a plunger rod lowers and the valve body rotates to the first position. It activates the plunger, which draws the sample into the central tube. The valve body rotates to position two and dispenses the sample through the active area. Here we see the organisms being trapped on the filter, while the remaining fluid is dispensed into a waste chamber. The valve body again rotates into position three. Then, it draws the first reagent into the central tube and through the active area. The piston then rotates into position four, drawing the second reagent through the active area. At this point, a sonic horn is engaged against the base of the valve body. Here we see the sonication, which breaks apart the organisms and releases the genetic material. Once the sonication is complete, the piston will push the liberated genetic material into the chamber that contains the first two reaction beads. These beads dissolve into solution with the genetic material. The piston again rotates now to position five and pumps the solution into the reaction tube at the back of the cartridge. After thermo cycling, the plunger returns the solution into the central tube, rotates the valve body, and pumps the solution into another chamber, where a second set of two reaction beads are dissolved. The piston again draws the solution back to the central tube, rotates and then dispenses the solution into the reaction chamber again for a second round of thermo cycling. Here we show six color detection and process. At this point, the assay is complete.