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Diagnosis and management overview

Diagnosing canine diabetes

Diabetes mellitus is not the only cause of polyuria/polydipsia and weight loss. Each dog should be examined thoroughly to rule out any other causes before starting insulin management. A preliminary diagnosis of diabetes mellitus based on clinical signs must be confirmed by blood and urine tests. Reference values for blood glucose range from 80–120 mg/dL (4.4–6.7 mmol/L) in dogs. The renal threshold is around 180 mg/dL (10 mmol/L). If the blood glucose concentration exceeds this threshold, glucose is excreted in the urine.

Presentation of a non-complicated diabetic dog

Two types of patients can be categorized as non-complicated:

  1. Dogs presented to the veterinarian after the dog owner has noted the appearance of clinical signs without general deterioration—that is, no diabetic ketoacidosis (DKA). These cases are not emergencies, although dogs without cataracts should be treated diligently to try to avoid this complication.
  2. Dogs that, after initial presentation with DKA and its successful treatment, are generally stable and without ketonuria.


The goals in managing diabetes mellitus are to minimize the clinical signs of diabetes, the risk of hypoglycemia, and the development of long-term complications. Accomplishing these goals requires that dog owners understand all aspects of diabetes management. Investment of sufficient time in a careful explanation of all of the aspects of the therapy is strongly recommended.

Managing diabetes can be an exercise in frustration until stabilization occurs; however, there are tools available to help evaluate the disease and its management, and there are resources available through this website to provide additional support.

Insulin forms one of the cornerstones of the management of diabetes mellitus; therefore, it is important to understand the length of action of insulin and how to evaluate management.

How to evaluate management

Available tools include:

Monitoring blood glucose is a good way to evaluate regulation of the diabetic dog. It is accurate, rapid, and requires only a drop of blood. However, in certain conditions (see below), it is not reliable because blood glucose concentration is influenced by many factors. Consequently, blood glucose curves may not show the actual result of the insulin treatment.

Various factors such as economics, logistics, and clinical situations can also force veterinarians to limit diagnostic procedures. When it is not possible to perform a complete glucose curve, punctual blood samples combined with clinical signs, general observations, and evaluating glycosuria can provide an overview of the diabetic animal. Veterinarians can also rely on evaluation of glycosylated hemoglobin (GHb) and fructosamine in laboratory testing.

Certain conditions

Food intake, exercise, dog cooperation, use of a drug (eg, xylazine, demetomidine, prednisolone, progestogens, megestrol acetate), and other conditions (eg, hyperadrenocorticism, acromegaly), or stress can affect blood glucose levels. In these cases, therefore, blood glucose measurement will not be helpful and other methods of evaluation should be used.