Direct Measurement of Free Thyroxine in Patients with T3-Toxicosis
22 April 2008 (online)
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.
Free T 4-Hyperthyroidism - T 3-Toxicosis