Dialysis is a mechanical process that partly performs the work that healthy kidneys would do. Hemodialysis uses a man-made membrane (dialyzer) to filter wastes, remove extra fluid from the blood, restore the proper balance of chemicals in the blood, and eliminate extra fluid (edema) from the body.

Before hemodialysis treatments can begin, a doctor will need to create an access where blood can flow in and out of the body (dialysis access). This is usually done by inserting a tube (catheter) into blood vessels in the forearm.

Hemodialysis is done in a hospital or dialysis center. A hemodialysis session usually lasts from 3 to 5 hours and must be done 3 times a week. A person can read, watch television, or sleep during dialysis sessions.