Free Thyroxine Index Range. Patients with hypothyroidism require a higher level of serum free thyroxine to achieve a normal tsh value in comparison with euthyroid control subjects. Thyroxine binding capacity (units are in thyroxine binding index:
T4, t3 ru, free t4 index, free t4, and t3 fall within the normal range or are low (figure 142.1 and table 142.4). A total t4 measures the bound and free hormone and can change when binding proteins differ (see above). Free thyroxine is often more useful than total thyroxine in assessing thyroid function.
Your results may be described as free t4 or free thyroxine index (fti).
How to interpret my free thyroxine test report? A total t4 measures the bound and free hormone and can change when binding proteins differ (see above). Reference ranges for the free thyroxine index: Normal ranges for free t4:
