This test measures the level of free thyroxine (Free T4) in your blood which is the unbound, active form of T4 available for conversion into the hormone T3. Free T4 plays a critical role in regulating metabolism, energy production, and overall thyroid function. Assessing Free T4 provides valuable insight into thyroid hormone balance and how effectively the thyroid is functioning independently of protein-binding effects.

Fasting is not required for this test.

A provider will approve your labs, and your Lab Requisition Form will be emailed to you within 24 business hours. Labcorp will also have this on file. Please bring a valid photo ID to your nearest Labcorp location. Results will be securely emailed as soon as they are available.