Free T4
$22.50
Plus a $12 blood draw fee, charged once per order. Free when your order includes a bundle.
- Sample
- Blood draw
- Preparation
- No fasting needed.
- Results in
- 2-4 business days after your sample reaches the lab
Tests are ordered by an independent licensed physician. This service does not replace care from your own doctor. Talk with a healthcare professional about your results.
This test measures free T4, the active thyroid hormone circulating in your blood. It’s used together with TSH to get a fuller picture of thyroid function.
People order it alongside TSH when thyroid symptoms are present or thyroid medicine is being monitored. If you take biotin supplements, ask your doctor whether to pause them before your draw — biotin can interfere with this kind of test.