title: Correlation of free thyroxine index and thyroxine: thyroxine-binding globulin ratio with the free thyroxine concentration as measured by the thyroxine and thyroxine-binding globulin radioimmunoassays.
abstract: The concentration of thyroxine-binding globulin in the serum can now be measured by a simple and specific radioimmunoassay. Triiodothyronine uptake and measurement of total thyroxine have been combined to yield a free thyroxine index which has been found to correlate with the clinical state of the patients. An estimate of the free thyroxine concentration, as measured by the thyroxine and thyroxine-binding globulin radioimmunoassays, provided a good correlation with the free thyroxine index and the thyroxine: thyroxine-binding globulin ratio. However, the thyroxine: thyroxine-binding globulin ratio is inaccurate when thyroxine-binding globulin concentrations are high or low.
mesh_terms: D000328:Adult; D003276:Contraceptives, Oral / Q000494:pharmacology; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood; D009230:Myxedema / Q000097:blood; D011863:Radioimmunoassay; D012044:Regression Analysis; D013974:Thyroxine / Q000097:blood*; D013975:Thyroxine-Binding Proteins / Q000032:analysis*
chemical_list: D003276:Contraceptives, Oral; D013975:Thyroxine-Binding Proteins; D013974:Thyroxine