Dialysis is a mechanical process that performs the work that healthy kidneys would do. It clears wastes and extra fluid from the body and restores the proper balance of chemicals (electrolytes) in the blood. When chronic kidney disease becomes so severe that your kidneys are no longer working properly, you may need dialysis. You may use dialysis to replace the work of the kidneys for many years, or it may be a short-term measure while you are waiting for a kidney transplant.

Before starting dialysis, your doctor will arrange to have a surgeon place a dialysis access in your body so that blood or body fluids can be transferred between your body and the machine. The type of access that you have depends on which type of dialysis you choose.

The two types of dialysis used to treat severe chronic kidney disease are hemodialysis and peritoneal dialysis.

• Hemodialysis uses a man-made membrane called a dialyzer to clean your blood. You are connected to the dialyzer by tubes attached to your blood vessels. Before hemodialysis treatments can begin, a surgeon creates a site where blood can flow in and out of your body. This is called the dialysis access. Usually the doctor creates the access by joining an artery and a vein in the forearm or by using a small tube to connect an artery and a vein. An access may be created on a short-term basis by putting a small tube into a vein in your neck, upper chest, or groin.
• Peritoneal dialysis uses the lining of your belly, which is called the peritoneal membrane, to filter your blood. Before you can begin peritoneal dialysis, a surgeon needs to place a catheter in your belly to create the dialysis access.

For more information about dialysis, see:

Which type of dialysis should I have?

What to think about

If you have severe chronic kidney disease but have not yet developed kidney failure, talk to your doctor about which type of dialysis would be best for you. Before starting dialysis, your doctor will arrange to have a surgeon place a dialysis access surgically in your body.

Both types of dialysis can be expensive. But Medicare or insurance may cover most of the costs. Check with your insurance or Medicare about your coverage. The dialysis center or hospital can help you find the best way to pay for your treatment.