How Is Diabetes Diagnosed in Pets? Tests Explained

How is diabetes diagnosed in dogs and cats?

A diabetes diagnosis is usually straightforward, but it often takes more than a single test — and knowing why helps the process make sense.

What does the vet look for?

Diagnosis rests on two things together: persistently high blood glucose, and the typical signs (increased drinking, urinating, appetite and weight loss). One high reading alone isn't enough, because glucose can rise temporarily for other reasons — so vets confirm the pattern rather than acting on a single number.

Why is a stressed cat a special case?

Cats are the reason vets are cautious about one-off readings. A trip to the clinic can spike a cat's blood glucose from stress alone — "stress hyperglycaemia" — mimicking diabetes. To tell the difference, vets use a fructosamine test, which reflects average glucose over the past few weeks and isn't fooled by a single stressful morning.

What tests are typically run?

Commonly: a blood glucose measurement, a urine test (glucose spilling into urine is a strong clue, and it also screens for infection), and often a fructosamine test to confirm. Your vet may also check for ketones — substances that build up when diabetes is dangerously out of control — and run broader bloods to check for other conditions that often accompany diabetes.

What happens after diagnosis?

Your vet will start insulin and set up a plan to find the right dose over the following weeks, with rechecks. This settling-in period is normal and temporary. Keeping a clear record from day one makes those early adjustments faster and safer.

Mello helps you capture exactly the readings and notes your vet needs during this crucial early phase.