Please Wait
{{vm.model.title}}
{{vm.model.overview}}
Recommended Products for You
Thyroxine Free, Direct (T4) Blood Test
Item # LC001974
Measures free thyroxine (T4), released from the proteins that carry it
Thyroxine Free, Direct (T4) Blood Test
Item # LC001974
Measures free thyroxine (T4), released from the proteins that carry it
This test is used to assess your thyroid hormone production. When T4 is released from the proteins that bind and carry it in the blood, it is free to convert to the more active thyroid hormone T3. Some health care providers prefer this test to the standard T4 blood test.
| The thyroid gland produces and secretes T4, otherwise known as thyroxine. Proteins bind to T4 and carry it throughout the bloodstream. Once in the tissues, T4 is released from the proteins and is now free to convert into the more active form called T3. For this reason, many doctors believe that measuring free T4 is a more sensitive test for thyroid hormone production. High levels of free T4 are associated with symptoms such as anxiety, insomnia, diarrhea, muscle aches, and pains. These symptoms collectively are known as hyperthyroidism. Low levels of free T4, known as hypothyroidism, are associated with symptoms such as depression, weight gain, dry skin, hair loss, constipation, and cold intolerance. Instructions Fasting is not required for this test. Take all medications as prescribed. Note For a more extensive evaluation of thyroid function, Life Extension® offers a Comprehensive Thyroid Panel. |
The laboratory services are for informational purposes only. It is not the intention of National Diagnostics, Inc and Life Extension to provide specific medical advice but rather to provide users with information to better understand their health. Specific medical advice including diagnosis and treatment will not be provided. Always seek the advice of a trained health professional for medical advice, diagnosis or treatment.
Both the physician and the testing laboratory are independent contractors with whom National Diagnostics, Inc makes arrangements for your blood tests. Neither National Diagnostics, Inc or Life Extension will be liable for any acts or omissions of the physician, the testing laboratory, or their agents or employees.
Why Life Extension?
100% Satisfaction Guarantee
Full one-year, no-hassle returns, money-back guarantee.
Highly Recommended
98% of our customers recommend us to family and friends. Life Extension is proud to be recognized as the #1 Catalog/Internet Brand 4 Time Winner.†
Complimentary, Personalized Guidance
Medical doctors, nutritionists & other health professionals are passionate about providing personalized solutions to help you achieve optimal health.
Efficacious Formulas
40 years of research dedicated to bringing you premium, scientifically-validated formulations.
Product Transparency
99% of our products are manufactured in the U.S, and a Certificate of Analysis is available for every product we produce.
Product reviews are provided for informational purposes only and reflect solely the views and opinions expressed by the contributors and not those of Life Extension. We do not verify or endorse any claims made in these reviews. Please read the full product reviews disclaimer.
Related Lab Test
Thyroid Panel (TSH, T4, Free T4, Free T3) Blood Test
A thyroid lab test that evaluates hormone levels
$56.25
