Insulin Tests in Dogs and Cats: When a Vet Measures It

Insulin tests measure the hormone that moves sugar from the blood into the body's cells. A vet may ask for one in a dog or cat with unexplained weakness, trembling or low blood sugar, and reads the result alongside a blood sugar value rather than on its own.

What does insulin do in the body?

Insulin is made by the pancreas, a small organ near the stomach. After a meal, sugar from food enters the blood, and insulin helps that sugar move into muscle and other tissues, where it is used for energy.

When there is too little insulin, or the body stops responding to it, sugar stays high in the blood. When there is too much insulin, sugar can fall too low.

Why is insulin read together with blood sugar?

An insulin number on its own says little. The same insulin level can be ordinary in a pet whose sugar is high after a meal and surprising in a pet whose sugar is very low. So the vet looks at the two together and asks whether the insulin fits the sugar.

If sugar is low while insulin is high, or is not as low as expected, the vet may think of a pancreas that is making too much insulin, for example because of a growth in the pancreas. That is a question to follow up with scans and further tests, not a conclusion from one report. The lab lists Insulin, Fasting for measuring the hormone, and your vet tells you whether the sample must follow a gap without food.

Which signs may point to low blood sugar?

Low blood sugar may show as sudden weakness, wobbling, trembling, odd behaviour, collapse or fits.

This is an emergency. Take your pet to a vet at once and do not wait for a lab report. Tests help to find the cause once your pet is safe.

How do sugar tests and fructosamine fit in?

Insulin is not the usual first test for diabetes. When a dog or cat drinks a lot of water, passes a lot of urine and loses weight despite a good appetite, vets usually start with blood sugar, often with a urine check.

• Glucose Fasting (FBS) measures sugar after a period without food.
• Glucose Random (RBS) can be taken at any time of the day.
• Fructosamine reflects the average sugar over the past few weeks.

A frightened cat can show a high sugar reading that comes only from stress at the clinic. Fructosamine is less swayed by one stressful visit, so it helps the vet see the longer pattern.

The Diabetic Safety Panel groups random sugar, a sugar check after a meal and HbA1c, a marker of longer-term sugar. It suits pets whose vet is already following their blood sugar, and your vet decides whether the bundle or single tests are right.

Should my pet fast before the test?

Only if your vet says so. Some of these tests ask for a gap since the last meal, but fasting is a medical decision. A very young or thin pet, a pet already under treatment for diabetes and a pet that turns weak when hungry can be harmed by a skipped meal. Never start or stop food, or change any treatment, on your own. Tell the lab if your pet has eaten.

Blood for sugar tests goes into a tube with an additive that stops the cells from using up sugar. In an ordinary tube the cells keep consuming sugar and the result can read falsely low. The person taking the blood uses the right tube, and if you carry a sample from your vet, ask the lab how to bring it.

How are the results read?

A registered veterinarian reads insulin and sugar results with your pet's signs, age, diet and history. One reading, especially from a nervous pet, can mislead.

Read next

A single blood marker rarely tells the whole story, and ESR in Pets: What the Sedimentation Rate Shows and Its Limits shows the same idea with a different test. Skin and coat problems have many causes, and Fungal Culture for Ringworm in Dogs and Cats explains one lab test for them. Ringworm can pass to people, so wash your hands after handling an affected pet and speak to a doctor if you notice skin patches.

Testing in Bhopal

Please call or WhatsApp +91 88175 01118 before the visit, so that the right tube and your vet's fasting advice are clear. Blood can be collected free anywhere in Bhopal, or brought to C-200, C Sector, Shahpura. From other districts, send it by courier, bus parcel or through your vet; the lab confirms the method, sample needs and reporting time when you book.