T4 (Thyroxine), Total

Formal Name of the Test:
T4 (Thyroxine), Total

Other Names Used:
T4 Total; Tetraiodothyronine

Sample Required:
Serum

Test Overview:
The amount of thyroxine, or T4, in the blood is measured by this test. The thyroid gland produces two primary hormones: T4 and T3. The total T4 test is performed to determine whether someone has hyperthyroidism or hypothyroidism. It’s a valuable test, but the amount of protein in the blood that may bind to the hormone can influence the results.

Test Preparation:
There is no need for any prior preparation. Stop biotin consumption at least 72 hours prior to the collection.

Test Performed at:
Quest Diagnostics, Test Code 867 
Click here to go to Quest Diagnostics page for this test