Free (Thyroxine) T4 can sometimes be indicated when binding globulin (TBG) problems are perceived, or when conventional test results appear inconsistent with clinical observations. It is common in subjects with high thyroxine-binding globulin hormone binding who are euthyroid (ie, free thyroxine should be normal in non-thyroidal diseases). It should appear normal in familial dysalbuminemic hyperthyroxinemia.