Device for extracorporeal blood treatment

A disposable cassette for a dialysis treatment, the disposable cassette comprising a rigid body having a first fluid pathway through which a first fluid flows, and a pressure measuring zone configured to be coupled to a pressure sensor of a reusable dialysis machine wherein the disposable cassette further comprises a second fluid pathway including a first end in fluid communication with the first fluid pathway and a second end having an opening covered by a flexible membrane forming the pressure measuring zone such that the pressure measuring zone transmits the first fluid pressure to the pressure sensor while the pressure measuring zone is offset from the first fluid pathway.