The diagnosis of diabetes mellitus relies on several different testing methods. Essentially, diabetes mellitus always results in an elevated blood glucose (blood sugar) level. The tests used to diagnose diabetes typically provide some form of measurement of glucose either in the blood or in the urine.
Canine and Feline Diabetes Mellitus May First Be Suspected From the Animal's History and Physical Examination
A dog or cat that is suffering from diabetes typically has certain symptoms, such as always being thirsty, urinating more than normal, eating more than usual or losing weight. As a pet owner, you can help your veterinarian diagnose diseases like diabetes mellitus by being on the lookout for these types of symptoms and reporting them to your veterinarian. This will help your veterinarian collect a good history on your pet and give her an idea where to focus her attention.
In dogs and cats, the diagnosis of any disease, including diabetes mellitus, relies on having a thorough physical examination done by your veterinarian. For dogs and cats with diabetes, the physical examination may reveal abnormalities related to the disease such as diabetic cataracts in dogs or an abnormal stance or gait caused by a diabetic neuropathy in cats.
Diabetes in Dogs and Cats - The Importance of Blood Glucose Testing
Once your veterinarian has completed the physical examination and collected an accurate history for pet, she will likely recommend some basic blood tests if she suspects diabetes mellitus.
In dogs and cats with diabetes, the blood glucose level is expected to be higher than normal. However, it is important to remember that this test alone is not sufficient to diagnose diabetes. Other factors besides diabetes can affect the glucose level in the blood and those factors must be ruled out as a cause of the elevation. In cats, even stress can cause the blood glucose to increase and most cats find a trip to the veterinarian stressful.
A blood glucose level is only a measure of the glucose level in the blood at the time the test is performed. It is similar to a snapshot, showing one single moment in time. It does not provide a measure of whether the blood glucose was elevated prior to or after that one test.
The blood glucose level is usually part of a routine blood screen and, in most cases, a blood screen will probably check for other issues as well, such as kidney function, liver disease and more.
Urine Testing and Diabetes in the Dog and Cat
Another test that your veterinarian will likely want to perform for your dog or cat is a urinalysis. This is a urine test that examines your pet's urine for various substances, including glucose and ketones.
In dogs and cats with diabetes, the urine is likely to contain excess glucose. If ketones are also present in the urine, it indicates that your pet's diabetes has reached a serious point and he will require immediate treatment to save his life.
Another part of the urinalysis that will help your veterinarian evaluate your pet's risk for diabetes is the specific gravity. The specific gravity of the urine is a measure of the concentration of the urine. Dogs and cats that have diabetes generally have very dilute urine and the specific gravity of the urine will be lower.
In most cases, a typical urinalysis will also test for other abnormalities in the urine such as blood, protein, red blood cells, white blood cells and others.
Because urinary bladder infections are common in dogs and cats with diabetes, your veterinarian may also recommend doing a urine culture and sensitivity on your pet's urine. A urine culture looks for evidence of bacteria in the urine and the sensitivity is used to determine which antibiotics the bacteria will be effective in killing or controlling the bacteria.
Fructosamine and Diabetes Mellitus
Fructosamine is a special blood test that is often performed in testing for diabetes mellitus. Fructosamine itself is a glycated protein, a protein that is bound to a glucose molecule.
Measuring the fructosamine level gives your veterinarian a measure of what your pet's blood glucose value has averaged over a two week period of time as opposed to a snapshot as with the blood glucose measurement. In diabetes, the fructosamine will be elevated.
Blood Glucose Curves and Diabetes in Dogs and Cats
The other test that is frequently done for diabetic dogs and cats is a blood glucose curve. A blood glucose curve is a series of blood glucose tests that are performed at regular intervals (usually every 1-2 hours) over the course of 12-24 hours. A blood glucose curve is helpful in monitoring the effectiveness of insulin in treating a pet's diabetes but is not helpful in the initial diagnosis of disease.