<p>A disposable cartridge (10) or use in a hemodialysis machine (1) has a blood flowpath for carrying a volume of blood to be treated in a 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 operatin of the cartridge (10).</p>
