Published by: Ingrid King. Last Updated on: July 22, 2023 by Crystal Uys

vet holding a senior cat

Chronic Kidney Disease (CKD) is a common disease in cats, especially senior cats. There are a number of different terms used for this condition, including Chronic Renal Failure, Chronic Kidney Insufficiency, or simply Kidney or Renal Disease. All of them mean that the cat’s kidneys are not functioning optimally.

CKD is different from acute kidney disease, which can strike at any age and is caused by a sudden event, such as ingestion of antifreeze, blood clots, a bacterial infection or kidney stones.

Healthy kidneys act like a filter to remove waste products from the body. They regulate electrolytes such as potassium and phosphorous, and they produce erythropoietin which stimulates red blood cell production. Kidneys produce rennin, which contributes toward regulating blood pressure. Kidneys also play a major role in turning vitamin D into its active form, which controls calcium balance in the body.

When kidney function becomes compromised, cats may not even show symptoms at first. However, the disease is progressive and damage is irreversible, which is why early diagnosis and intervention is so important.

Diagnosing CKD

Your vet will run a blood chemistry panel and a urinalysis to measure the concentration of the urine. Urine concentration decreases as kidney function is lost. Your vet may also recommend additional tests to rule out infection.

Cat blood tests
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The 4 Stages of CKD

Once kidney disease is diagnosed, it is “staged,” which means a determination is made, based on lab values, about how much the disease has progressed. There are four stages of CKD.

Stage 1

The creatinine level in the blood (a measure of how well kidneys are performing) is lower than 1.6, which means that less than 66% of kidney functions have been lost. Cats will most likely not show any clinical signs while in Stage 1.

Stage 2

The creatinine level is between 1.6 and 2.8, which means that 66% to 75% of kidney function has been lost. Clinical signs are usually mild or absent at this stage.

Stage 3

The creatinine level is between 2.9 and 5.0, which means that 76% to 90% of kidney functions has been lost. At this stage, typical signs of kidney disease, such as increased thirst and urination, weight loss, lack of appetite, and weakness, are usually noticeable. At this stage, cats may benefit from subcutaneous fluid administration to support remaining kidney function and prevent dehydration.

Stage 4

The creatinine level is higher than 5.0, which means that at least 90% of kidney function has been lost. At this end stage, cats are usually very sick. Loss of appetite, poor grooming and lethargy may be very pronounced. Cats may need more frequent fluid administration.

For a more detailed and indepth look at the stages of CKD, take a look at the IRIS (International Renal Interest Society) Staging Guidelines.

Treating CKD

There is no cure for CKD, but proper treatment can keep cats happy and healthy for quite some time after diagnosis, in some cases, for years. Therapy is aimed at minimizing the buildup of toxic waste products in the bloodstream, maintaining adequate hydration, addressing disturbances in electrolyte concentration, supporting appropriate nutrition, controlling blood pressure, and slowing the progression of the disease.

Once your cat has been diagnosed with CKD, you should work closely with your veterinarian to monitor the progression, but always keep in mind that you’re treating the cat, not the lab values. Even though your cat’s test results may indicate that she is in the latter stages of the disease, she may still appear and act healthy.

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8 Comments on The 4 Stages of Chronic Kidney Disease: Signs, Diagnosis & Treatment

    • Hi Jane,

      Hi, we are very sorry to hear that your cat’s creatinine is above the values that are considered normal.
      In order to be able to interpret these values properly, your cat should be starved at the time of the blood test and well hydrated. Your veterinarian is the best person to interpret these results and tell you what stage of chronic kidney disease your cat is in (if this is the cause) and how best to help. You can read the following article for some information:

      All the best!

  1. It’s one of the hardest things to confront. I’ve lost two cats to CKD. I have given them the LRS drip and it’s been hard on me and even worse on them. To see them waste away and know that there is no cure…pretty harsh. I’ve decided that I won’t do the drip ever again. I feel like it stresses the cat, it hurts the cat, and they still die. It’s only a very temporary relief and the stress it causes them isn’t good either. Is anyone studying any other medication that can get their kidneys to function again?

  2. My cat Maggie is 21. She’s been diagnosed with kidney disease for several years. She took a downturn in August 2020. One of our vets suggested with try a human medication called Epigen. It is used to treat anemia associated with kidney disease. The vet said from her experience that cats respond well for a few months but will eventually stop working. Maggie has now had this weekly injection since they first started it in August 2020. There have been a few weeks where she started losing weight. She has now regained the weight she lost. She’s now at 7.4 pounds. The only other medication she’s on is predisolone for IBD. It has certainly helped to extend her life.

  3. Tasha has a history of “crystals” in her urine. I have her on a mixture of Dry CD and Indoor Advantage. I hope to prevent any issues for her.

  4. This is a good explanation of chronic kidney disease in cats, but the best place on the web for advice on ALL aspects of treating it is at Tanya’s website at Tanya was a cat who had CKD, and her person created this award winning site in her memory. It has hundreds of pages (and a search function) that are continually updated.

    There is a related group at with lots of kind, experienced people who will respond to your day-to-day questions and provide emotional support. Some of the more active members know more about CKD than a lot of vets do. They provide tips and techniques that will improve your sick kitty’s quality of life, and may even extend it.

    I can’t recommend these two resources highly enough. Both of them are free–and both are priceless.

    • Tanya’s page has been a fantastic resource for a long time, and I agree, it’s priceless even for experienced cat parents. I always encourage people to not let the dated design of the site detract from the wealth of information.

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