Thyroxine (T4) Free Direct Serum
- Free T4, Direct, Serum
- Free Thyroxine
- T4, Free, Direct, Serum
- Unbound T4
Free T4 may be indicated when binding globulin (TBG) problems are perceived, or when conventional test results seem inconsistent with clinical observations. It is normal in subjects with high thyroxine-binding globulin hormone binding who are euthyroid (ie, free thyroxine should be normal in nonthyroidal diseases). It should be normal in familial dysalbuminemic hyperthyroxinemia.