What is T3 Free (FT3) test?
The unbound or free triiodothyronine hormone (FT3) is readily available for uptake into cells. This differs from the bound/total hormone, T4 (FT4) that is not immediately available for uptake into cells. The FT3 test measures only free/unbound triiodothyronine hormone (FT3).
Why get the T3 Free (FT3) test?
Free T3 helps in determining thyroid dysfunction in patients with symptoms of hypothyroidism or hyperthyroidism, but who have normal TSH values. Free T3 measurements can be useful to determine appropriate medication and dosage even in those with high or low TSH.
When to take this test?
AnytimeEvery 6 monthsNo particular precautions are required, unless it is recommended by your doctor.FT3