Thyroid Function Tests: Free thyroxine index
The American Thyroid Association has recommended that the entity most commonly known as the free thyroxine index (TI, or T-7, T-12, Clark and Horn index) be renamed the free T4 index (FT4I). The FT4I was developed to correct the T4 assay for effects of thyroxine-binding protein alterations. It consists basically of the serum T4 result […]