Description

A Free T4 test, or thyroxine test, measures the amount of free thyroxine (T4) in your blood. T4 is a hormone produced by the thyroid gland that helps determine how well your thyroid is working. A free T4 test can help diagnose and monitor thyroid disease and can also help determine if the problem is with your thyroid or pituitary gland.

Fasting not required.