Thyroxine (T4)
Short Description
Thyroxine (T4) is the main hormone produced by the thyroid gland. This blood test measures levels of T4 to help in the diagnosis of thyroid disease.
Long Description
To produce thyroxine, the thyroid gland needs iodine from the food we eat. Thyroxine is called T4 because it contains 4 atoms of iodine. Although it is the most plentiful of the thyroid hormones, it is not biologically active and does not govern metabolism in our cells. That job is undertaken by triiodothyronine, or T3. T4 converts to T3 by the removal of an atom of iodine.
Thyroxine is typically measured in thyroid function tests because a low T4 reading is likely to indicate insufficient levels of T3 (and therefore a slow metabolism) while high levels of T4 tend to lead to excess T3 (resulting in an overactive metabolism).
Special Instructions
Why Take This Test
2 days turnaround
Not recommended
1 biomarkers included
Gender:
Take This Test If You Are:
Related Products
Non-Key Biomarkers
- Total Thyroxine