Thyroxine Free T4 Range. Conditions associated with hyperthyroidism include graves disease, an autoimmune disorder. A normal t4 test result means your thyroid gland works like it should.
However, it’s important to note that different labs and doctors may have a varying “normal range.” The free t4 index includes a formula that compares free and bound t4. Most patients will feel well in that circumstance.
Free t4, which tests for the amount of t4 that is available in the body, should range between 0.8 to 1.8 nanograms per deciliter (ng/dl).
Free thyroxine is often more useful than total thyroxine (total t4) in assessing thyroid function, but total t4 can be a useful biomarker in some cases. Most patients will feel well in that circumstance. Almost all of the t4 in the blood (99.97%) is bound to blood proteins, but only the unbound t4 is active. If you recall from basic thyroid physiology, your free t4 levels act as a reservoir or pool to draw upon when your body needs to create the active thyroid hormone free t3.
