Diabetes is one of the most frequent endocrine diseases in dogs and its prevalence is increasing. In 1999, 58 out of 10,000 dogs in veterinary hospitals were diagnosed with diabetes. It is now estimated that 1 of 200 may be diabetic. Despite these numbers, there are no internationally accepted criteria for the classification of canine diabetes. There are no laboratory tests that can tell if a dog is going to develop diabetes and no tests to identify the underlying cause of the diabetes in your dog.
Diabetes is generally diagnosed later in the disease course when clinical signs become evident. The most common signs are polyuria (excessive urination), polydipsia (excessive thirst and drinking), and sudden unexplained weight loss. Increased appetite is commonly seen despite weight loss.
To diagnosis your dog, the level of the glucose in the blood must be determined. An isolated blood test may lead your vet to suspect diabetes, but several tests repeated, all showing an elevated blood glucose level, are necessary to confirm the diagnosis of diabetes.
A normal biochemical value for blood glucose in dogs is 60-125 mg/dl. Applying diagnositic criteria used for humans, any glucose level higher than the normal should be repeated. Consistently elevated levels will confirm a probable diagnosis of diabetes mellitus.
Your dog will be started on insulin upon diagnosis and will be monitored. If blood sugar levels do not appropriately respond to the administration of insulin over time, your veterinary will want to investigate the presence of other disorders.
Tilley LP, Smith FWK. The 5-minute Veterinary Consult, Canine and Feline. 3rd ed. 2004.
Rand JS, Fleeman LM, Farrow HA, Appleton DJ, Lederer R. Canine and Feline Diabetes Mellitus: Nature or Nurture? http://www.uq.edu.au