Published by: Ingrid King. Last Updated on: February 1, 2023 by Crystal Uys


This post is sponsored by IDEXX Laboratories

Chronic Kidney Disease, also known as Chronic Renal Failure (CRF) is a common condition in aging cats. It is the result of a gradual decrease in kidney function. 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.

New biomarker provides early warning

SDMA, short for symmetric dimethylarginine, is a new biomarker for kidney function. Since SDMA is almost exclusively eliminated by renal filtration, it is a good estimate of glomerular filtration rate (GFR), an indicator of how well the kidneys are working.

Currently, kidney disease is diagnosed by testing blood levels of creatinine and BUN, and by urinalysis. However, since creatinine levels are dependent on lean body mass, an underweight cat in renal failure may have normal blood creatinine levels, so the diagnosis of kidney failure could be missed if only a blood chemistry is run. SDMA is not influenced by muscle mass.

Earlier detection allows for better treatment success

Travis Pond, DVM, the owner of American Pet Hospital in Las Vegas, NV, was part of a field trial of the new test. “We used the test on about 100 cats over a period of two to three months,” said Dr. Pond. They found elevated SDMA levels in a few older cats that were not showing any symptoms of kidney disease, but a more common scenario was that the blood chemistry came back with borderline values. “These were the cases where we would be scratching our heads, wondering whether this was real kidney failure, or whether the cat was just dehydrated at the time the blood was drawn,” said Dr. Pond. “The SDMA marker helped clarify the other values.”

Dr. Pond’s clients have been very receptive to the new test. “I was impressed with how educated my clients were,” said Pond. “They knew about kidney disease, and they understood how important it was to diagnose it early.”

Earlier detection will lead to more successful treatment via medical and dietary means. Medical intervention can include increasing hydration by eliminating dry food, providing plenty of fresh water, and using supplements or medications that protect kidney function.

Diet changes may include phosphorus and sodium restriction. Many vets still recommend so-called prescription diets with restricted protein, but the studies that have evaluated the effect of reduced protein diets did not evaluate long term effects on the whole cat. Protein restriction causes muscle wasting, which is associated with decreased longevity and quality of life. Cats will actually use amino acids in their own muscle if inadequate protein is fed. There may be some benefit to reducing protein in the late stages of kidney disease.

Ask your vet about the SDMA test

Be sure to ask your vet about this test the next time you take your cat in for her check up. Dr. Pond recommends the SDMA test for cats as young as five years old, as kidney changes can start at that age. The test should definitely be included in preventive diagnostics for cats age six or older.

For more information about the SDMA test, please visit the IDEXX Laboratories website.

FTC Disclosure: This post is sponsored by IDEXX Laboratories, which means that I was compensated to feature this content. Regardless of payment received, you will only see products and information featured on this site that I believe will be of interest to you.

About the author

20 Comments on New Test Detects Kidney Disease Early

  1. I wish they wouldn’t talk about this until it was already out! I had to get Jack’s blood work done and I am lamenting I couldn’t wait to get this.. but we just couldn’t wait any longer.

  2. Very interesting article and all follow up comments. We have two cats, now 15 years old , who have renal failure and both on Renal diets …. supposedly. George is not so keenand tends to still eat normal stuff, Ella is happy with the dried and she does seem to be not so far down the track; but I do wonder if there is any sort of “remission” with this disease because George recently has shown signs of not being so affected by it and has become more as he has always been. I know they are both on borrowed time, but as you so wisely say, we have to make the most of the time they have with us. Each cat will react differently I imagine – have certainly noticed it with the two mentioned here.

  3. Hi Ingrid, and thanks for this valuable info. 1 of my boys died of this wretched disease; it is heartbreaking. I have heard that feeding seafood to pets is a contributing factor in kidney disease, along with the plastic liners coating the tins wet food comes in leaking toxic materials. Could you please share your thoughts about what contributes to CKD? It seems it is prevalent in cats. Thank you.

    • I’m sorry about your boy, Elizabeth. I don’t think anybody knows exactly what is causing this prevalence of kidney disease. While I don’t recommend feeding fish (because of the potential for contamination with heavy metals and other toxins,) I don’t think a direct correlation between a diet high in fish and CKD has been established. BPA in cat food cans has been linked to thyroid disease, so it’s possible that there’s a connection to kidney disease as well. I do, however, believe that nutrition plays a key role, especially dry food. Dr. Elizabeth Hodgkins, a holistic veterinarian, shares some indepth information on this issue in her book:

  4. Thank you so much for sharing this! We caught Jewel’s CRF “early” but so much damage had already been done.

    I will definitely talk to our vet about this test for Milita. Her kidney values had increased with her last test (though they were still in normal range) so anything we can do to help her as early as possible would be wonderful.

  5. Thank you so much for this article. My sweet boy Clark had this disease when I adopted him and it was hard to be doing everything possible to have it be not enough:( Early detection could help save so many…

  6. I am so familiar with this terrible disease. Two of my cats died of it. My cat Sabrina, how just turned 13, has it too. I have a tech. come to the house 4 times a week to give her fluids and pills. It’s very stressful not knowing how long she will be with me. She sits on my lap during the process and I can feel her shaking a bit. She is very good about it (better than I am) but giving her a pill is no easy task. Just thought I would share my story.


    • I know it’s hard, Nunzie. What I’ve learned from living with a cat with a terminal illness (Buckley) is to try to stay in the moment as much as possible and treasure the time you have with her rather than worrying about the end. I know that’s easier said than done sometimes, but ultimately, the only thing we can do.

  7. Thanks Ingrid … Norwegian Forest Cats seem to be prone t poly cystic kidney disease. Casey Jones already has one kidney smaller than normal. Would this test be something that would help with early diagnosis or is this a whole different avenue? As you know, he was traumatized terribly during an emergency surgery & very long & arduous process during & after. He stresses out unbelievably when he goes to the vet, even for well check ups, and will refuse water, food and social interaction for a few days after. I give him water through a syringe for a few days. So I decided that I would only take him when necessary. I’m wondering if you would you consider this test a necessary evil for his situation? Thanks in advance, Joyce

    • I would discuss this with your vet, Joyce. With a cat like Casey Jones, you always have to weigh the stress of a vet visit vs. the benefits of putting him through testing. Have you considered a vet who will come to your house? Do you think that would make it easier?

      • I did, and I found someone. We had her come to the house as a guest a couple of times to see how he responded just to her visit. He was distant, unusual for him even with new people. He wasn’t uninterested, he kept watching her. But he wouldn’t let her near him, kept backing out of the room or running away and making that deep throated stay the hell away from me sound. Eventually he just hibernated which he will do only when he doesn’t feel well. I guess I’ve pretty much decided that with Casey, I’m going to let him dictate his life. I love him too much to see him suffer .. through ANYTHING. I promised him I’d never put him through surgery, for anything at all, again. So I think I’m going to just stay on this route. When Casey shows me he doesn’t enjoy eating, playing & running after his sister, or cuddling & being a part of the family, then I’ll know he’s pretty much made his own decision. Thanks for the input. I reckon I knew the answer already ….

  8. This is awesome! The moment the SDMA test is available here, both Binga and Boodie will be getting it – I’m only a few months over a year old, so I’m a ways off from that test yet.

Leave a Reply

Your email address will not be published. Required fields are marked *