Free Thyroxine (Free T4)
Also known as: Free T4, FT4, Thyroxine
Not near Sutton Coldfield? Have this blood test anywhere in the UK
We offer blood tests across the UK through our partner network: have your sample taken at The Vesey or at a partner clinic near you, anywhere in the UK and Ireland. A Health Advisor books it for you on a free 15-minute call, and your results come back to The Vesey for our GPs to review.
Free thyroxine (free T4) is the unbound, active fraction of the main hormone produced by the thyroid gland. At The Vesey in Sutton Coldfield, Free Thyroxine is available within 18 private blood test panels, with clinician-reviewed results. This page is educational and does not replace personalised medical advice.
What Free Thyroxine measures
Free thyroxine (free T4) is the unbound, active fraction of the main hormone produced by the thyroid gland. Measuring the free portion reflects the hormone available to the body’s tissues.
Why it is tested
Free T4 is measured alongside TSH to build a clearer picture of thyroid activity. It is often included when thyroid symptoms are being investigated or when a TSH result needs further interpretation.
Tests that include Free Thyroxine at The Vesey
Guide prices are read from the current Vesey catalogue and confirmed at booking.
Thyroid
Guide price from £148
Fertility
Guide price from £210
Standard Screen Plus (Female)
Guide price from £210
Standard Screen Plus (Male)
Guide price from £210
Tired All The Time?
Guide price from £217
Fertility + STI
Guide price from £220
12 further Vesey panels include Free Thyroxine. See all blood test panels →
Related biomarkers
Other markers in the thyroid group:
Frequently asked questions
Why measure free T4 rather than total T4?
The free fraction reflects the hormone actually available to tissues, whereas total T4 is affected by binding proteins in the blood. This is why free T4 is the form usually reported.
This page is for general education and information only. It is not medical advice, a diagnosis, or a recommendation for any specific test or treatment, and it does not include reference ranges, which are laboratory-dependent and interpreted by a clinician. Guide prices are indicative and confirmed at the time of booking. Always discuss your health and any test results with a qualified clinician. In an emergency call 999; for urgent non-emergency advice call NHS 111.
Private blood testing in Sutton Coldfield
Clinician-reviewed results. No GP referral needed.
Not sure which blood test to book?
Book a free 15-minute video call with one of our Health Advisors. We talk through your symptoms or goals, recommend the right test and book it for you. No charge, no obligation.
Not near Sutton Coldfield? We offer blood tests across the UK through our partner network. This call is how a partner clinic appointment is booked: we complete the paperwork and arrange it for you, anywhere in the UK and Ireland.
Book a free discovery call or call 0121 387 3705