Dialysis is a procedure that replaces some of the work healthy kidneys do. It is done when you lose about 85–90% of your kidney function. It may also be done earlier if your symptoms may be improved by dialysis. During dialysis, wastes, salt, and extra water are removed from the blood, and the levels of certain chemicals in the blood (such as potassium) are maintained. Dialysis is done in sessions. Dialysis sessions are continued until the kidneys get better. If the kidneys cannot get better, such as in end-stage kidney disease, dialysis is continued for life or until you receive a new kidney (kidney transplant). There are two types of dialysis: hemodialysis and peritoneal dialysis.


Hemodialysis is a type of dialysis in which a machine called a dialyzer is used to filter the blood. Before beginning hemodialysis, you will have surgery to create a site where blood can be removed from the body and returned to the body (vascular access). There are three types of vascular accesses:

  • Arteriovenous fistula. To create this type of access, an artery is connected to a vein (usually in the arm). A fistula takes 1–6 months to develop after surgery. If it develops properly, it usually lasts longer than the other types of vascular accesses. It is also less likely to become infected and cause blood clots.

  • Arteriovenous graft. To create this type of access, an artery and a vein in the arm are connected with a tube. A graft may be used within 2–3 weeks of surgery.

  • A venous catheter. To create this type of access, a thin, flexible tube (catheter) is placed in a large vein in your neck, chest, or groin. A catheter may be used right away. It is usually used as a temporary access when dialysis needs to begin immediately.

During hemodialysis, blood leaves the body through your access. It travels through a tube to the dialyzer, where it is filtered. The blood then returns to your body through another tube.

Hemodialysis is usually performed by a caregiver at a hospital or dialysis center three times a week. Visits last about 3–4 hours. It may also be performed with the help of another person at home with training.


Peritoneal dialysis is a type of dialysis in which the thin lining of the abdomen (peritoneum) is used as a filter. Before beginning peritoneal dialysis, you will have surgery to place a catheter in your abdomen. The catheter will be used to transfer a fluid called dialysate to and from your abdomen. At the start of a session, your abdomen is filled with dialysate. During the session, wastes, salt, and extra water in the blood pass through the peritoneum and into the dialysate. The dialysate is drained from the body at the end of the session. The process of filling and draining the dialysate is called an exchange. Exchanges are repeated until you have used up all the dialysate for the day.

Peritoneal dialysis may be performed by you at home or at almost any other location. It is done every day. You may need up to five exchanges a day. The amount of time the dialysate is in your body between exchanges is called a dwell. The dwell depends on the number of exchanges needed and the characteristics of the peritoneum. It usually varies from 1.5–3 hours. You may go about your day normally between exchanges. Alternately, the exchanges may be done at night while you sleep using a machine called a cycler.


Both hemodialysis and peritoneal dialysis have advantages and disadvantages. Talk to your caregiver about which type of dialysis would be best for you. Your lifestyle and preferences should be considered along with your medical condition. In some cases, only one type of dialysis may be an option.

Advantages of hemodialysis

  • It is done less often than peritoneal dialysis.

  • Someone else can do the dialysis for you.

  • If you go to a dialysis center, your caregiver will be able to recognize any problems right away.

  • If you go to a dialysis center, you can interact with others who are having dialysis. This can provide you with emotional support.

Disadvantages of hemodialysis

  • Hemodialysis may cause cramps and low blood pressure. It may leave you feeling tired on the days you have the treatment.

  • If you go to a dialysis center, you will need to make weekly appointments and work around the center's schedule.

  • You will need to take extra care when traveling. If you go to a dialysis center, you will need to make special arrangements to visit a dialysis center near your destination. If you are having treatments at home, you will need to take the dialyzer with you to your destination.

  • You will need to avoid more foods than you would need to avoid on peritoneal dialysis.

Advantages of peritoneal dialysis

  • It is less likely than hemodialysis to cause cramps and low blood pressure.

  • You may do exchanges on your own wherever you are, including when you travel.

  • You do not need to avoid as many foods as you do on hemodialysis.

Disadvantages of Peritoneal Dialysis

  • It is done more often than hemodialysis.

  • Performing peritoneal dialysis requires you to have dexterity of the hands. You must also be able to lift bags.

  • You will have to learn sterilization techniques. You will need to practice them every day to reduce the risk of infection. 


Both hemodialysis and peritoneal dialysis require you to make some changes to your diet. For example, you will need to limit your intake of foods high in the minerals phosphorus and potassium. You will also need to limit your fluid intake. Your dietitian can help you plan meals. A good meal plan can improve your dialysis and your health.


Adjusting to the dialysis treatment, schedule, and diet can take some time. You may need to stop working and may not be able to do some of the things you normally do. You may feel anxious or depressed when beginning dialysis. Eventually, many people feel better overall because of dialysis. Some people are able to return to work after making some changes, such as reducing work intensity.


National Kidney Foundation: www.kidney.org

American Association of Kidney Patients: www.aakp.org

American Kidney Fund: www.kidneyfund.org