Specimen: Blood

Results: 1-3 business days

Description: The Free T4 test is used to assess the thyroid's function and to help diagnose diseases or disorders of the thyroid like hyperthyroidism and hypothyroidism. Thyroxine, also know as T4, is one of the two main thyroid hormones. T4 affects nearly every physiological process in the body including regulating heart rate, metabolism and the body's temperature. Free thyroxine (FT4) is T4 that is not bound to proteins in the blood; as such, this blood test is not affected by protein levels and is therefore a more reliable measurement of T4 levels in the blood. The free T4 test is thought by many to be a more accurate reflection of thyroid hormone function and, in most cases, its use has replaced that of the total T4 test.

*Please note: The result turn around time is an estimate only and not guaranteed. The reference lab may need additional time due to conditions with the weather, confirmation or repeat testing, or equipment maintenance and other reasons out of our control.