Diabetes in Dogs and Cats: Glucose, Fructosamine and HbA1c

Diabetes mellitus (sugar disease) happens when a dog or cat does not make enough insulin, or its body cannot use insulin well, so sugar stays high in the blood. A glucose test shows the sugar level at one moment, while fructosamine and HbA1c show the average over past weeks, and your registered veterinarian reads them with your pet's signs and history.

What is diabetes in pets?

Insulin is a hormone made by the pancreas, an organ near the stomach. It moves glucose (sugar) from the blood into the body's cells, where it is used for energy. Without enough working insulin, sugar builds up in the blood and spills into the urine, while the body's cells go short of energy.

Diabetes is most often seen in middle-aged and older pets. In dogs it is usually because the body does not make enough insulin. In cats, being overweight raises the risk.

Signs to watch for

• Drinking much more water than usual
• Passing much more urine, or accidents in the house
• Eating well, or more than before, but losing weight
• Tiredness and less interest in play
• In dogs, cloudy eyes, because cataracts can form
• In cats, weak back legs and walking low on the back legs

These signs often build up slowly, so owners may notice them late. Kidney disease, urine infection, womb infection and other hormone problems can also cause thirst and heavy urination. Tests are needed to find the cause.

If a pet with these signs vomits, becomes very weak, breathes fast or collapses, go to a vet at once.

Glucose, fructosamine and HbA1c compared

• Glucose Random (RBS) shows the sugar level at the moment of the sample. It can rise after a meal, and fear or stress can raise it, especially in cats. One high reading is not enough to diagnose diabetes. A fasting glucose is taken after a period without food, and a post-prandial glucose is taken some time after a meal, as your vet advises.
• Fructosamine shows the average sugar level over about the last two to three weeks. It measures sugar attached to blood proteins. A single stressful vet visit changes it much less than a glucose reading. So it can help tell stress-related high sugar from diabetes, and it can show how well sugar has been controlled.
• HbA1c measures sugar attached to haemoglobin, the oxygen-carrying protein in red cells, and it reflects a longer period than fructosamine. It is used less often in pets, and anaemia can affect it.

Some conditions that change blood proteins or red cells can affect these results. Your vet reads them together with other tests.

How the tests are used

To find diabetes, vets look at three things together: blood sugar that stays high, sugar in the urine and the typical signs. Sugar in the urine is a useful clue, but it is not enough on its own. A urine test can also show ketones, which are acids that build up when the body burns fat for energy instead of sugar. Ketones can signal a more serious stage.

A visit usually goes like this:

1. Your vet examines your pet and asks about thirst, urine, appetite and weight.
2. A small blood sample is taken, and urine is collected if possible.
3. The lab measures glucose, and fructosamine or HbA1c if your vet asks for them.
4. Your vet reads the results with your pet's signs and plans the next steps.

The Diabetic Safety Panel groups random glucose, post-prandial glucose and HbA1c. Glucose is measured on blood collected in a special tube that stops blood cells from using up sugar before the test.

Ask your vet exactly what to do about food on the day of the test. A pet on diabetes treatment must not skip meals or change its treatment on its own before a test.

After a diagnosis

Diabetes can usually be managed. Your vet will plan the treatment, the diet, the feeding routine and how often to repeat tests. Fructosamine can show how well sugar has been controlled over recent weeks. Do not change the plan or skip treatment on your own. A healthy weight and regular check-ups help, particularly in cats.

When to talk to your vet

Book a visit if your pet drinks and urinates much more than usual, or loses weight in spite of a good appetite. Before the visit, note how much water your pet drinks in a day, how often it urinates, its appetite and any weight change. Tell your vet about all medicines, because some medicines can raise blood sugar.

See a vet at once if a pet with diabetes is weak, wobbly, shaky, has a fit or collapses. Very low or very high blood sugar can both be dangerous.

Pashupatinath Vet Lab provides free sample collection anywhere in Bhopal. Call or WhatsApp +91 88175 01118 to book. From other towns, samples can be sent to the lab by courier, bus parcel or through your local veterinarian. You can browse all lab tests for Dog and Cat on this website.