Thyroxine - Free (FT4)

What is a free T4 test?
The free thyroxine test (FT4), often called a free T4 test, measures the quantity of free thyroxine in your blood. T4 circulates within the blood in two forms: free morpheme (FT4) and bound morpheme. Thyroxine (T4) is a hormone secreted by the thyroid and is important for growth and metabolism. The FT4 test helps to diagnose any suspected thyroid disease (hypothyroidism or hyperthyroidism) and check the treatment efficacy in people diagnosed with a thyroid condition.