A blood test that measures your dog’s blood glucose level is the most common diagnostic tool, but a high glucose level does not always mean diabetes. Because other diseases sometimes raise these levels, your vet may run additional tests to rule out such causes.
Once your dog is diagnosed, her veterinarian will obtain a “serial blood glucose–concentration curve” by measuring her glucose level repeatedly over many hours. The results will help the vet choose an appropriate insulin, dose and dosing schedule.
After treatment starts, your dog will need to be routinely tested to see how well the protocol is working. Most commonly, either a fructosamine test or a glycated hemoglobin test, which reveal average control over the previous one to three weeks (fructosamine) or two to four months (glycated hemoglobin) is used. In contrast, the daily blood glucose measurement is a snapshot, an indication of your dog’s glucose level at one specific moment.
In the long run, the label your vet gives your dog’s diabetes isn’t important. A good treatment plan is what matters. Treating diabetes is as much an art as a science. The goal of treatment is to keep blood glucose levels close to normal—roughly between 65 and 120 mg/dl—so that your dog feels good now and is less likely to develop diabetes-related problems later. The most common diabetic complication in dogs is cataracts (clouding of the lens of the eye); over time, dogs may also develop hardening of the arteries, kidney disease, retina disease or nerve disease. And because bacteria thrive on a high-sugar diet, dogs with diabetes are prone to gum, urinary, skin and other infections. Other components of treatment include proper diet, weight loss (if your dog is overweight), an exercise program and home testing of blood glucose levels.
•Insulin. With rare exceptions, dogs with diabetes need one to two daily insulin shots to survive; the insulin is injected just under the skin. Your vet may prescribe a human insulin, or possibly Vetsulin, which is a purified pig insulin; Vetsulin is the only insulin approved for use in dogs in the U.S. Insulins vary greatly in how quickly they start working, when their action peaks, how long they last and how much they cost. Your vet will take these factors into account when choosing the best type for your dog.
•Home monitoring. Weigh your diabetic dog regularly and watch for signs of excess hunger, excess thirst and excess urination, indicators that her glucose levels may be too high. Regular testing of your dog’s blood glucose level can reveal problems before they become emergencies. Glucose levels rise after meals, occasionally when your dog is sick, and when the insulin dose is too low or timed improperly; they drop during fasting, after exercise, and when the insulin dose is too high or timed improperly. Both too-high and too-low levels can be dangerous.
Testing also lets you know how well the treatment program is working.“It’s extremely important that a clear understanding be developed of the meaning of blood glucose monitoring,” says William D. Schall, DVM, professor in the Veterinary Medical Center at Michigan State University in East Lansing. When interpreting the results, consider when your dog last ate, how much exercise she has had recently, when she received an insulin dose, how large the dose was and any symptoms.
Testing involves pricking a hairless area with a lancet, collecting the blood drop that wells up and using a small device called a blood glucose meter to measure the concentration of glucose in the sample. Many dog owners use human blood glucose meters. However, these meters tend to read low for dogs. The AlphaTRAK meter is designed for dogs and cats and requires only a tiny blood sample. “Whichever glucose meter is used, the results should be compared at some point to the results obtained by the veterinarian’s laboratory by performing simultaneous samples,” says Louise Murray, DVM, DACVIM, director of medicine at the American Society for the Prevention of Cruelty to Animals in New York City.
When your dog is sick, the vet will also want you to test your dog’s urine for ketones (a poisonous byproduct of fat breakdown); you may need to do that on a regular basis as well.