Thyroxine (also called T4) is one of the major hormones produced by your thyroid.
When T4 is created, some of the hormone gets bound to proteins, while the rest circulates freely.
It is the most important and sensitive test for hypothyroidism.
ER Productions Limited / Getty Images
Most healthcare providers will recommend having your blood drawn before you take any medications, if possible.
Location
A free T4 test will likely take place right in your healthcare providers office.
The results of a free T4 test vary depending on your age, gender, and health history.
Results of a free T4 test are just a glimpse of how your thyroid is functioning overall.
Together, you could treat your specificthyroid disordereffectively with minimal side effects.
Harvard Health Publishing.Thyroid hormone: How it affects your heart.
Carvalho GA, Perez CL, Ward LS.The clinical use of thyroid function tests.Arq Bras Endocrinol Metabol.
2017;11(6):CC13-CC16.
doi:10.7860/JCDR/2017/25604.9989
American Thyroid Association.Thyroid function tests.
Blood Test: T4 (Thyroxine).
Kids Health From Nemours website.
Thyroxine (T4) Test.
U.S. National Library of Medicine Medline Plus website.
American Thyroid Association website.
University of Rochester Medical Center website.
