title: Direct measurement of free thyroxine in patients with T3-toxicosis.
abstract: Circulating levels of free thyroxine were directly measured using a new kinetic radioimmunoassay system. Free thyroxine was abnormally elevated in: 1) each of eleven hyperthyroid individuals having elevated concentrations of thyroxine and triiodothyronine; and 2) all five hyperthyroid subjects who had normal circulating levels of thyroxine but elevated concentrations of triiodothyronine (T3-toxicosis). Using this assay system, free thyroxine appears to be elevated in all hyperthyroid individuals.
mesh_terms: D006801:Humans; D006980:Hyperthyroidism / Q000097:blood*; D008297:Male; D011863:Radioimmunoassay; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D014284:Triiodothyronine; D013974:Thyroxine