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Q&A: Does My Cat Have Kidney Failure, Or Is It Something Else?

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Dr. Mark is a veterinarian. He works with dogs, cats, exotics, and livestock.

There are many factors that contribute to a diagnosis of feline kidney disease.

There are many factors that contribute to a diagnosis of feline kidney disease.

Can I Get a Second Opinion on My Cat's Kidney Disease?

"I took in a male 6-year-old cat from the streets and am fostering him. (Six years old was my vet's estimate from looking at his teeth.) The vet diagnosed him with 70 percent kidney failure after an ultrasound and a blood test. He did not have a urinalysis done, and his blood pressure was not checked.

They told me to give him folic acid and VetIQ urinary care paste and to change his diet. Should I supplement with a phosphate binder as well? Can you give me your opinion about this case?" —Rema

Key Metrics for Assessing Feline Kidney Function

Having all of those tests done without completing a urinalysis is like going to a mechanic with a car that will not start and him saying "I will rebuild your car" without checking to see if the battery is even hooked up. Failing to test for phosphorus or blood pressure is equally problematic.

Moreover, no one can estimate age accurately based on teeth. Your cat might be 6 or just as likely be 10 or 12. (As a feral, he may have been eating mostly songbirds, feathers and all, and therefore not have the dental disease often seen in a 6-year-old house cat.)

In all honesty, I'd recommend finding a different vet immediately.

Kidney Disease and Nonregenerative Anemia

It sounds like your cat has kidney disease and nonregenerative anemia because his kidneys are no longer producing the hormone needed to make new blood cells. Folic acid can help when no blood cells are produced because of vitamin deficiencies, but not when there is no hormone produced. (Supplementing his diet with folic acid is not hurting, just a waste of resources.)

High Blood Pressure

Many cats with kidney disease also have high blood pressure, which needs to be treated. If your vet cannot test it, you should take your cat to a feline specialist. (Not everyone has this capability, myself included since I do not see that many cats, so you will need to call around before going for a new opinion.)

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Urinalysis for Diabetes

Besides the kidney disease, I would also be concerned about that glucose level. A urinalysis would tell us if the glucose level was just due to stress, as stress can cause high blood sugar levels in all cats, especially sick ones. (1) If no glucose is found in the urinalysis, then diabetes is not even likely, which is one reason those results are so important.

How to Help a Cat With Kidney Problems

  • Feed moist food. The dietary change is the most important thing you can do for your cat. Your vet has probably already chosen a kidney-disease diet appropriate for your cat, but you should make sure that you are giving moist food so that he consumes as much water as possible.
  • Get a cat water fountain. If you do not already have one, be sure to invest in a cat water fountain, which does tend to increase water consumption for some animals.

B vitamins may not need to be supplemented but your veterinarian probably decided they were needed based on the physical exam.

Avoid Giving Cranberry Supplements to CKD Cats

I am not sure about that other supplement you are giving since there is no evidence that it is of any use in cats. The main ingredient is malt syrup, a compound that is high in sugar. Here is a link to the ingredients and what it is normally used for.

The veterinarian who suggested this may have done so based on the urinalysis results, but it is not a good idea to give cranberry supplements to cats with chronic kidney disease (CKD). This article discusses why it is not a good idea to give cranberry supplements to cats.

Don't Use a Phosphate Binder Without Appropriate Testing

The phosphate binder is a really bad idea without knowing if your cat has high levels of phosphorus in the blood. I do not know why they did not test for it when you took your cat in the first place, but it needs to be rechecked after the cat has been on the kidney diet anyway.

A cat's body needs phosphorus for the cells in the heart, brain, and muscles. If there is none, those cells stop working.


  1. Laluha P, Gerber B, Laluhová D, Boretti FS, Reusch CE. Stresshyperglykämie bei kranken Katzen: Eine retrospektive Studie über 4 Jahre [Stress hyperglycemia in sick cats: a retrospective study over 4 years]. Schweiz Arch Tierheilkd. 2004 Aug;146(8):375-83.

This article is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from your veterinarian. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2022 Dr Mark

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