The invention relates to a hemodialysis system comprising a blood component portion including a blood pump； a blood cassette (150) operatively connected to the blood pump such that the blood pump can pump blood through the blood cassette (150) when the blood cassette (150) is in fluid communication with a blood source； a dialyzer fluidly connected to the blood cassette (150)； a dialysate component portion separate from the blood component portion, the dialysate component portion including a dialysate pump； and a dialysate cassette (10e) separate from the blood cassette (150), the dialysate cassette (10e) operatively connected to the dialysate pump such that the dialysate pump can pump dialysate through the dialysate cassette (10e) when the dialysate cassette (10e) is in fluid communication with the dialysate source, the dialysate cassette being fluidly connected to the dialyzer.
