Free T4
This lab test helps to evaluate thyroid function.
Free T4 Overview
Reviewed: April 22, 2014
Updated:
Free T4 is the active form of thyroxine, and is thought by many to be a more accurate reflection of thyroid hormone function. In most cases, its use has replaced that of the total T4 test.
Free T4 is measured in nanogram/
Technique
Blood draw
Preparation
Fasting is not required before the test
What the results mean
Increased free T4 may indicate Graves' disease and hyperthyroidism.
Lower than nornal free T4 may indicate hypothyroidism and may be seen with a goiter.
