Thyroid tests measure hormone levels in your pet's blood to check for an overactive thyroid, which is common in older cats, or an underactive thyroid, which is more common in dogs.
We often include thyroid testing in senior bloodwork, and we use it to monitor pets on thyroid medication so we can keep their dose right.
Signs Your Pet May Need a Thyroid Test
Thyroid changes often come on slowly, so they are easy to miss at home. Your vet may recommend testing if your dog or cat shows any of these changes:
- Weight changes that don't match how much your pet is eating
- A bigger or smaller appetite than usual
- Drinking and urinating more than normal
- Restlessness or low energy, such as a cat who seems hyper or a dog who sleeps much more
- Skin and coat problems, like thinning fur, a dull coat or repeat skin infections
- Vomiting, diarrhea or a fast heart rate, especially in older cats
If you notice any of these signs, mention them at your pet's next visit or schedule an exam sooner.
What to Expect During Thyroid Testing
Thyroid testing starts with a small blood sample, usually taken from a leg or the neck. Most pets handle it well, and it often takes just a few moments. Your vet may run a basic thyroid level first, then recommend more specific tests if the first result is borderline or doesn't match your pet's signs.
Thyroid results are best read alongside a physical exam and other bloodwork. Other illnesses and some medications can lower thyroid levels in dogs, so our team looks at the whole picture before making a diagnosis. If your pet is already on thyroid medication, your vet will let you know when to bring them in for rechecks and whether timing the test around their dose matters.
Questions about Thyroid Testing?
Call us or book an appointment online, and our team will help you decide on the next step for your pet.
Thyroid Testing: Frequently Asked Questions
Does my pet need to fast before a thyroid test?
How often should a pet on thyroid medication be tested?
Can a thyroid test be wrong?
At what age should my pet start thyroid screening?
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