This is a comprehensive blood test that measures three important thyroid hormones—Free T3 (Triiodothyronine), Free T4 (Thyroxine), and Thyroid Stimulating Hormone (TSH).
These hormones play a vital role in regulating metabolism, energy levels, body temperature, and overall hormonal balance. Free T3 and Free T4 represent the active forms of thyroid hormones, while TSH controls their production.
The purpose of this test is to:
The Free TFT (Free Thyroid Function Test) measures three important thyroid-related hormones: Free T3 (FT3), Free T4 (FT4), and TSH (Thyroid-Stimulating Hormone). Together, these tests provide a broader assessment of how well the thyroid gland and the pituitary-thyroid system are functioning.
Free T3 is the biologically active form of triiodothyronine available to body tissues, while Free T4 measures the unbound portion of thyroxine circulating in the blood. TSH is produced by the pituitary gland and regulates the thyroid's production of T4 and T3.
The combination is commonly used to evaluate hypothyroidism, hyperthyroidism, thyroiditis, and other thyroid-related disorders. It can also be useful for monitoring people who are already receiving treatment for a thyroid condition. Results are interpreted together because an individual hormone value alone may not provide a complete picture of thyroid function.
1. What is included in the Free TFT test?
The Free TFT includes Free T3, Free T4, and TSH. These tests assess circulating thyroid hormones and the pituitary signal that regulates thyroid activity.
2. What can abnormal Free T3, Free T4, and TSH levels indicate?
Different combinations can suggest conditions such as hypothyroidism or hyperthyroidism. However, results must be interpreted together with symptoms, medications, medical history, and the laboratory's reference ranges.
3. Is fasting required for the Free TFT test?
Generally, fasting is not required for thyroid function testing. However, certain medicines and supplements, particularly biotin (vitamin B7), can interfere with some thyroid test results. Inform your healthcare provider about supplements and medications you take, and follow any specific preparation instructions provided.