Overview of Dialysis for Kidney Failure

When your kidneys begin to fail, you will typically go through stages of loss of kidney function over time. The stages are from stage 1 through 5 of chronic kidney disease (CKD). Stage 5 kidney failure is when many people need either dialysis or a kidney transplant.

The purpose of kidneys is to clean the blood and turn waste into urine. Dialysis is a medical procedure that helps clean the blood when kidneys cannot.

People can have mild kidney disease (stage 1-3) and never end up at stage 5.

Dialysis machine and patient
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Kidney disease comes with a long list of complications. In the early stages of chronic kidney disease, these complications are treated with medications and dietary changes. These complications include high blood pressure, abnormal electrolytes, and swelling.

Eventually, people who do get to stage 5 might have complications that are harder to treat. This is when people need a kidney transplant or dialysis if a transplant is not possible.


Kidney disease has 5 stages. If disease makes it to stage 5, this is called kidney failure, and it requires a kidney transplant. Transplants are not always possible for every patient, so those patients go through a process called dialysis.

Overview of Dialysis

Dialysis is an artificial way of replacing some of the kidneys' functions. The kidney does a lot of important functions in the body. Here is a brief summary:

  • The kidneys control and maintain safe levels of important electrolytes. These include sodium and potassium.
  • They regulate the amount and concentration of water in your blood.
  • They make a hormone that is used to make red blood cells, called erythropoietin.
  • They make sure that your bones stay healthy by producing a form of vitamin D.
  • They dump extra acid that is made 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

There are different kinds of dialysis. One technique is called hemodialysis. Hemo is the Greek word for blood. "Blood dialysis" is when the patient's blood is circulated through a machine that has a filter that copies the kidney's filtration function. After the blood goes through this filter, called the dialyzer, the purified blood is returned to the patient.

Hemodialysis is usually done in a dialysis center about three times every week, for three to four hours. The exact time it takes 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 do the procedures yourself. Once you are comfortable doing it, they will let you do it at home.

Home Hemodialysis

Home hemodialysis may happen as often as five to seven times per week. The time for each session is adjusted by your kidney doctor based on your needs.

Peritoneal Dialysis

Another kind of dialysis that is also done at home is called peritoneal dialysis. Peritoneum refers to the abdominal cavity.

In this type of dialysis, a soft plastic tube called a catheter, is permanently inserted into the patient's peritoneum through the abdomen. Dialysis fluid is then put into the peritoneum. This fluid sits there for a few hours while it cleans the blood and balances electrolytes. Then, the fluid is drained out, and another round of fluid is added.

This cycle is repeated a few times. It usually happens at night using a machine called the "cycler." In the morning, the patient unhooks the cycler and puts a cap on the catheter.

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


The kidneys perform many important functions for the body. When kidneys aren't working, either hemodialysis or peritoneal dialysis replace some of these functions. These are done at home or at a dialysis center. There is either a needle or catheter that pulls blood into a machine for cleaning and then returns the clean blood to the body.

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 this because a catheter sits permanently on their belly. One of the needles in the shunt will take blood from the body to the dialysis machine. The other one will carry back the clean blood from the machine to the patient.

The shunt 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, which is called a fistula. The surgeon might instead use an artificial tube, or graft, to make this connection.

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


Chronic kidney disease may get to stage 5 and need either a transplant or dialysis. A transplant is not possible for certain patients. Dialysis helps clean the blood when kidneys cannot. There are different types of dialysis that can happen at a dialysis center or at home depending on the patient.

Both hemodialysis and peritoneal dialysis are a process where the blood is pulled from the body into a machine for cleaning. The clean blood is then returned to the body. This process happens a few times each week depending on the patient's needs.

A Word From Verywell

From a medical standpoint, no study has proven any type of dialysis better than the other. It is more of a lifestyle choice. Patients usually prefer home dialysis if they have the ability to take care of themselves. This option is good for patients who 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 can get clogged or infected. Peritoneal dialysis catheters can have the same issues. It comes down to what works best for you. While you figure out this process, it may be smart to look into getting on a transplant list, as well.

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7 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