The Total T4 test evaluates the concentration of thyroxine (T4) in your pet’s bloodstream. This hormone is critical for regulating metabolism. In dogs, low T4 levels typically indicate hypothyroidism, leading to lethargy, weight gain, and skin issues. In cats, high T4 levels often suggest hyperthyroidism, a common condition in older cats marked by weight loss, increased appetite, and restlessness. This test is key for diagnosing and monitoring thyroid disorders.

Q: What does T4 measure in pets?
A: It measures thyroxine, a hormone made by the thyroid that regulates metabolism.

Q: What are signs of hypothyroidism in dogs?
A: Weight gain, hair thinning, low energy, and intolerance to cold.

Q: What are signs of hyperthyroidism in cats?
A: Weight loss despite eating more, vomiting, increased thirst, and hyperactivity.

Q: How is the sample taken?
A: A small blood sample is collected by your veterinarian.

Q: Is fasting needed?
A: Not required, but some vets may recommend fasting for clarity.

Q: Can medication affect results?
A: Yes. Medications like steroids or thyroid supplements can alter T4 levels.

Q: Can this test be done alone?
A: Yes, but often paired with Free T4 or TSH tests for full thyroid evaluation.

Q: Is it painful for my pet?
A: No, it's a standard blood draw with minimal discomfort.

Q: How often should T4 be checked?
A: Once a year for seniors or as needed if symptoms arise.

Q: Can young pets have thyroid issues?
A: It's rare but possible. Thyroid disease is more common in older pets.

Q: Is this test expensive?
A: No, it's a mid-range test offering high diagnostic value.

Q: How long does the test take?
A: Results are usually available within 24–48 hours.

Q: What happens if my pet’s T4 is abnormal?
A: Your vet may recommend additional thyroid testing or start medication.

Q: Will my pet need lifelong treatment?
A: Often yes, especially in hypothyroid dogs and hyperthyroid cats.

Q: Can diet affect thyroid function?
A: Yes, especially iodine levels. Your vet may suggest prescription food.