Overview of Dialysis for Kidney Failure

When your kidneys begin to fail, you will typically go through progressive stages of loss of kidney function. These stages are classified from stage 1 through 5 of chronic kidney disease (CKD). Stage 5 kidney failure is when many people start to require either dialysis or a kidney transplant. Not everyone who starts off with mild kidney disease (stage 1-3), will progress to stage 5.

Dialysis machine and patient
Science Photo Library / Brand X Pictures / Getty Images

Kidney disease comes with a long laundry list of complications. In the early stages of chronic kidney disease, these complications are typically treatable with medications and dietary changes. That is, medications should suffice to treat complications like high blood pressure, abnormal electrolytes, swelling or edema (that are expected to occur in CKD). However, eventually, if you do happen to progress to advanced kidney disease, or CKD stage 5, these complications begin to be harder and harder to treat with medical management alone. At this time, should you not get a kidney transplant (or if you are not eligible for it), you will often need dialysis.


Dialysis is an artificial way of replacing some of the kidneys' functions. The kidney performs a lot of essential functions in the body, beyond just making urine. Here is a brief summary: 

  • The kidneys regulate and maintain the levels of essential electrolytes like sodium and potassium within a range that is safe for normal life.
  • They regulate the amount of water in your blood, and hence the concentration of your blood.
  • They produce a hormone that is essential to make red blood cells, called erythropoietin.
  • They make sure that your bones stay healthy by producing a form of vitamin D.
  • They dump excess acid that is generated from normal metabolism out of your system.
  • Very importantly, they help maintain your blood pressure.

Dialysis attempts to replace some, but not all of these functions.


How dialysis is performed depends on the kind of dialysis. One technique is called hemodialysis. Hemo is the Greek word for blood. Hence "blood dialysis" is when the patient's blood is taken from a "dialysis access" and circulated through a machine that has a filter that mimics the kidney's filtration function. Once the blood goes through this filter (called the dialyzer), the purified blood is returned to the patient. Hemodialysis is typically performed in a "dialysis center" (in-center hemodialysis), where it is usually done about three times every week, for three to four hours (this depends on the patient's size).

At-Home Dialysis

Both hemodialysis and peritoneal dialysis can be performed by patients themselves at home. Your nephrologist and a dialysis nurse will train you for a few weeks on how to perform the procedures yourself. Once you are comfortable doing it, they will let you do it in the comfort of your home.

Home Hemodialysis

This technique might be performed as often as five to seven times per week, with the time for each session adjusted by your kidney doctor based on your needs.

Peritoneal Dialysis

Another kind of dialysis that is also performed at home is called peritoneal dialysis. Peritoneum refers to the abdominal cavity. In this modality, a permanent catheter is inserted into the patient's peritoneum through the abdominal wall. Dialysis fluid is then instilled into the peritoneum, and this fluid sits there for a few hours while it clears the blood of toxins and balances electrolytes. Then, the fluid is drained out, and another round of fluid is instilled. This cycle is repeated a few times (typically at night using a machine called the "cycler"), and in the morning, the patient unhooks themself from the cycler and caps the catheter.

For any type of at-home procedure, you will still need to be seen about once a month by your nephrologist, and you will have both the nephrologist and a dialysis nurse available on call for troubleshooting. Dialysis nurses will often schedule a visit to your home in case it is something that cannot be taken care of on the phone.

Dialysis Access

A dialysis access or shunt is the site where two needles are inserted when someone is receiving hemodialysis (patients on peritoneal dialysis will not have such a shunt, but rather a catheter that sits permanently on their belly). One of the needles in the shunt will channel blood from the body to the dialysis machine, and the other one will carry back the clean blood from the machine to the patient.

The shunt itself is really a connection between an artery and a vein. It is placed by a surgeon, who might use your own vein to create this connection (this is called a fistula) or might use an artificial tube to make this connection (this is called a graft).

Sometimes a temporary catheter called a "vascath" (which is essentially a large IV) is placed into one of the large blood vessels in the body. This is done for patients that need emergency dialysis or those that are waiting for their permanent dialysis access to be placed by a surgeon.

A Word From Verywell

From a medical standpoint, no study has proven any modality to be necessarily better than the other. It is more of a lifestyle choice. Home dialysis is often preferred by patients who have the ability to take care of themselves, are proactive, do not want to be "tied down" to a dialysis center, or want to travel frequently. All types of dialysis come with pros and cons. Dialysis access sites may form fistulas or shunts can get clogged or infected. Peritoneal dialysis catheters can have the same issues; it comes down to what works best for you. While you navigate this process, it may be smart to start looking into getting on a transplant list, as well.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Kidney Foundation. Quick reference guide on kidney disease screening.

  2. U.S. National Library of Medicine, MedlinePlus. Chronic kidney disease. Updated August 1, 2017.

  3. National Institute of Diabetes and Digestive and Kidney Diseases. Your kidneys and how they work. Updated June 2018.

  4. National Institute of Diabetes and Digestive and Kidney Diseases. Hemodialysis. Updated January 2018.

  5. National Kidney Foundation. Your dialysis care team. 2015.

  6. National Institute of Diabetes and Digestive and Kidney Diseases. Peritoneal dialysis. Updated January 2018.

  7. Zee J, Zhao J, Subramanian L, et al. Perceptions about the dialysis modality decision process among peritoneal dialysis and in-center hemodialysis patientsBMC Nephrol. 2018;19(1):298. doi:10.1186/s12882-018-1096-x