In medicine, hemodialysis is a process that involves removing blood from the body and passing it through a dual compartment dialyzer before replacing it in the body. Blood goes through one compartment in the dialyzer and dialysis fluid goes through the other. The compartments are separated by a semipermeable membrane. In this way, waste such as potassium, uric acid and water are removed, even when the kidneys are unable to do so (for example, in case of renal failure.)

Hemodialysis is usually done in a dedicated facility, for example in a special room in a hospital or clinic that has nurses and technicians who are specialized in hemodialysis. Less typically, dialysis can also be done in the patient’s home.