A disposable cartridge (10) comprising a dialyser or adapted to receive a dialyser and use of said cartridge in a hemodialysis machine (1), wherein the cartridge has a blood flowpath for carrying a volume of blood to be treated in the dialyser and a dialysate flowpath, isolated from the blood flowpath, for delivering a flow of dialysate solution through the dialyser. The cartridge (10) is received in an engine section (4) of the machine (1). The engine section (4) has first and second platens (5, 6) which close when the cartridge (10) is inserted to retain the cartridge (10). Actuators (7) and sensors (8) arranged on the second platen (6) control operating of the cartridge (10).