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Thyroxine Free, Direct (T4) Blood Test
Item # LC001974
Measures free thyroxine (T4) available for conversion to T3
Thyroxine Free, Direct (T4) Blood Test
Item # LC001974
Measures free thyroxine (T4) available for conversion to T3
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.
A clinician's order is required for many tests. Where applicable, an independent clinician will review your test request and determine whether to authorize the test, if appropriate. For additional information, see PWNHealth Terms of Service.
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