Why Does My Veterinarian Want to Test My Cat for Diabetes?

Cats are masters at concealing their illnesses. The signs of most cat health problems are very subtle in the beginning. Diabetes mellitus, once referred to as “sugar diabetes,” is no exception. Because cats are private and secretive some of the signs of diabetes may go unnoticed by their guardians.

Many of the signs of diabetes are non-specific. Subtle increases in water intake and urine output may go undetected, especially in outdoor cats1.

Cats and people are similar in that we may miss the early signs. Many people have undiagnosed, subtle diabetes that, left uncontrolled, will progress to serious diseases. Cats are similar. A mild elevated blood sugar level may be insignificant or may be a precursor for full-blown diabetes.

How will my veterinarian test my cat for diabetes?
While an elevated fasting blood glucose level is strong evidence of diabetes, even in people, repeated fasting tests may be needed to confirm a diagnosis of diabetes–that test is called a glucose tolerance test. In cats, obtaining an accurate blood glucose level can be a challenge. The simple act of collecting blood from a cat can cause them to become agitated and result in an impact on blood sugar levels. Detection of glucose in the urine significantly increases the likelihood that diabetes is present, but not always. Blood sugar levels can be elevated to twice normal before glucose is detected in the urine1.

Many cat owners are not familiar with another blood test called fructosamine--a test that measures a byproduct of glucose metabolism rather than glucose itself. It is of particular value in cats. A serum fructosamine level is used to confirm the diagnosis of diabetes in most feline cases. Serum fructosamine concentrations are probably the most reliable and easiest way of evaluating your cat’s response to insulin therapy and are evaluated in conjunction with blood glucose curves and recheck examinations. It is a simple test and some veterinarians include this as part of their routine evaluation of cats they consider to be at risk.

Advantages of measuring fructosamine are that it:

  1. Distinguishes hyperglycemic, non-diabetic animals from diabetics with chronic hyperglycemia
  2. Is not influenced by stress hyperglycemia
  3. Is of value in confirming the diagnosis of diabetes and monitoring the response to treatment.

Diabetes can present real challenges in the initial diagnosis and management, but cat owners and veterinarians are interested in the same thing--keeping your cat healthy.

If you have any questions or concerns, you should always visit or call your veterinarian -- they are your best resource to ensure the health and well-being of your pets.


1. The Signs, Diagnosis & Types of Diabetes Mellitus in Cats, Pet

A Potential Game Changer for Pets with Diabetes


When Olaf, a four-year-old Siberian husky, was diagnosed with diabetes in February, there wasn’t anything his owners, Gina and Brian Dacey, wouldn’t do to help him. “We’ve had him since he was a few weeks old, and he’s really still just a baby,” Gina Dacey said.

Pets with diabetes cannot properly use glucose—a type of sugar found in the blood and the main source of energy for all the body’s cells. Glucose levels are primarily controlled by a hormone called insulin, which in pets with diabetes is either not produced or is insufficient for healthy living. Diabetic animals, just like many humans with the condition, must receive carefully timed daily injections of insulin to avoid developing life-threatening complications from their disease.

Already juggling the schedules of two small children and work, the couple rearranged their life to ensure someone would always be home to give Olaf his twice-daily insulin injections. “It’s definitely been a lifestyle change and learning curve for all of us—especially Olaf, who’s used to getting treats from his human sister,” Dacey said. “Now my three-year-old daughter will tell him, ‘You can’t have a treat, because you have diabetes and we have to watch your blood sugar.’”

However, despite the family’s best efforts, Olaf’s blood-sugar levels proved difficult to normalize, and the husky developed cataracts, a complication of his uncontrolled disease. “On Easter, I called his veterinarian sobbing because we noticed he was having trouble seeing,” Dacey recalled. “I didn’t know what to do, because everything we had tried—insulin adjustments, longer and more frequent exercising—wasn’t helping enough.”

Her veterinarian suggested that a longer-acting insulin might offer better blood-sugar control. While Dacey was researching options—learning that these products for humans can be purchased for pets—she stumbled across a free clinical trial of a new ultra-long-lasting insulin for dogs. [Editor’s Note: Updating this story, as of October 28, 2019, the free clinical trial studying an ultra-long-lasting insulin for feline diabetes also is now enrolling cats.] For the study at Cummings Veterinary Medical Center, veterinarian Orla Mahony is investigating whether a new insulin can control glucose levels in dogs using a single weekly injection.

Although diabetes is already usually very treatable in companion animals, “having a diabetic pet is a big commitment for any owner, and it’s not doable for everyone,” explained Mahony, a board-certified small-animal internist who specializes in endocrinology. “Diabetic pets typically require an insulin injection twice daily, and those injections are timed—they are not just given whenever you happen to be at home. That has an enormous impact on pet owners, who can no longer work late or sleep in on the weekends. For people who need to travel a lot for work, it can be an especially huge issue.”

The new insulin “is potentially a game changer,” said Mahony, a clinical assistant professor at Cummings School. “If it’s successful, owners could give their pets an injection just once a week, removing the need to be home at the same time every day,” she said. “And although the majority of pets take their shots without a bother, some pets really fight them, so reducing the number of injections would improve quality of life for these animals and their owners. We also think that using an ultra-long acting insulin will lead to better control of pets’ diabetes.”

In the Cummings School study, dogs with stable diabetes that are otherwise healthy receive four weekly injections of the new insulin, administered at the Foster Hospital. If it’s effective in their pet, owners then will have the option of continuing to use the insulin at home for a year after the trial ends.

In addition to this clinical trial, which is part of a multi-institutional study that includes UC Davis School of Veterinary Medicine, Mahony is working to launch a trial of a weekly insulin injection designed for cats. Both insulins were created by a Massachusetts biopharmaceutical company that develops products for human and veterinary medicine. Currently, long-lasting insulins are available in human medicine, but the injections only control blood-sugar levels for two or three days, according to Mahony.

After reading about the Tufts clinical trial, Dacey applied to enroll Olaf, and soon after the husky received the ultra-long-lasting insulin as the first case in the study. Dacey said Olaf is doing much better on the new treatment. “His personality has improved,” she said. “He has so much more energy that we went out for a run this morning—something that wasn’t possible when his sugars were not well controlled.”

Meal Timing for Dogs With Diabetes

After your dog eats, its blood glucose level will increase. Insulin will work to drive the glucose levels back down and keep them within a normal range.

If your dog gets one dose of insulin daily, the first meal should be 2/3 of the daily ration and be given before you give the insulin injection. You will give your dog the second meal with the final third of the daily ration six to eight hours later.

If your dog is given insulin twice daily, it should be fed two equally-sized meals 10 to 12 hours apart, with each meal given at the time of the insulin injections (or just prior). Don't give a larger and smaller meal as the dose of insulin will be aimed at meals of the same size.

It's best not to use a self-feeder or allow a dog with diabetes to be free feeding. Your dog needs the structure of having meals timed with insulin administration for management of diabetes to be the most effective.

Treatment of Cat Diabetes

Unfortunately, there is no known cure for cat diabetes. Treatment is focused on managing the illness and typically involves insulin injections. Most diabetic cats require daily insulin injections to manage the illness, which your vet can train you to provide at home. Schedule regular checkups to monitor your cat's blood sugar and her response to the treatment.

If obesity is a factor, you'll also need to make changes to your cat's meals. Two different types of meal plans have been shown to help control both weight and blood sugar in diabetic cats. One is a meal plan that's high in fiber and complex carbohydrates. The other is a low-carbohydrate, high-protein plan. Your vet might place your kitty on a prescription food for diabetes, but determining which one is right for your cat might require some experimentation.

No matter what form your kitty's treatment takes, you'll need to closely monitor your pet, keeping track of her appetite and how often she drinks water and urinates, as well as keeping an eye out for signs of complications. If you're willing, you might also be able to monitor your cat's blood sugar with a home glucose testing kit rather than taking her to the vet every time she needs to be checked. Talk to your vet about your options if you think you and your kitty might be good candidates for home testing.

While cat diabetes is a lifelong condition, it is by no means doesn't mean your cat can't live a fulfilling life. With proper management and treatment, cats with diabetes can live long and happy lives. So if your cat shows any symptoms of diabetes, we highly recommend a visit to your vet to determine the best course of action. The sooner it can be diagnosed and treated, the better it will turn out for your precious pet.

Contributor Bio

Jean Marie Bauhaus

Jean Marie Bauhaus is a pet parent, pet blogger and novelist from Tulsa, Oklahoma, where she usually writes under the supervision of a lapful of furbabies.

OK, you’re doing great with your diabetic pet. Insulin shots are a piece of cake. You’re doing glucose curves or having fructosamine checked. (here’s the article that covers those). Why does your vet keep wanting a urine sample?

Diabetic dogs and cats are very prone to developing urinary tract infections, or UTI’s. Even if your pet’s insulin dose is ideal, there will be times of high blood sugar right around when they are due for their next shot. It’s just how it goes. So it’s very common to have sugar in the urine of any diabetic animal, well-managed or not!

This sugar makes great food for bacteria. The bladder is basically a petri dish, waiting for bacteria to come in and thrive. Obviously, female dogs are more susceptible, given their anatomy. For male dogs, it’s a long and winding road from the outside world to the bladder, but some bacteria make the voyage!

Checking a urinalysis routinely is a great idea. We can detect bladder infections this way, as well as check for ketones. However, urinalyses are not always reliable, particularly if the urine is very watery (from the pet drinking a LOT of water).

Photo courtesy of

Worse news – a bladder infection / UTI can actually cause an animal to be insulin resistant! So if you’re giving insulin, feeding the right food, yet the water consumption has not got down at all, there could be a UTI lurking in there!

The best test to rule out an infection is a urine culture. This involves collecting the urine in a sterile fashion (can’t use the sample sucked off the floor this time!). We send it to the lab and they put the urine on a petri dish, then wait to see what grows. Even better, once they grow the bacteria, they can tell us which antibiotic will work, and which ones the bacteria is resistant to. No sense in giving an antibiotic that the bacteria in the bladder is just going to laugh at, right? Once we know which antibiotic kills the bacteria, your veterinarian will likely want to treat your pet for longer than an “uncomplicated” UTI, so prepare for 2-3 weeks of medication.

Also, monitor your dog or cat for any new symptoms, such as trying to urinate more frequently, accidents in the house, or licking “down there.” This could indicate a bladder infection, so mention it to your vet!

Diabetes is complicated! Check out the rest of the series:

Check out our podcast episode about diabetes. In an hour, we couldn’t even cover every detail, but you’ll learn and laugh with us along the way!

Watch the video: My cat has Neuropathy see what it looks like! (July 2021).