Hemodialysis is the most common treatment for kidney failure.
During this process, blood is drawn – usually from the forearm – and is pumped through a dialyzer. A dialyzer is a machine that acts as an artificial kidney.
A semipermeable membrane in the dialyzer separates blood from dialysate, a fluid with a chemical composition similar to blood plasma. Wastes, including urea, diffuse from the blood into the dialysate.
"Cleaned" blood now re-enters the body, and the used dialysate is discarded.