A hemodialysis machine including a main body and a door, the door being capable of opening and closing relative to the main body so as to receive and retain a disposable cartridge therebetween, the machine further including a controller and a pneumatic pump, the cartridge having a chassis with a platen side covered by a first deformable membrane and a door side covered by a second deformable membrane, the chassis and membranes defining a dialysate flow path for delivering a flow of dialysate solution through a dialyzer, the main body having a platen for in use sealing against the platen side of the cartridge and the door having an interface plate for in use sealing against the door side of the cartridge, the pneumatic pump being fluidically connected to an interface plate cavity between the interface plate and the cartridge by a pneumatic supply line, the pump being controlled by the controller to selectively generate a vacuum in the platen cavity so as to affix the cartridge to the door prior to operation of the machine.
