title: Serum free thyroid hormones in T3-toxicosis: a study of 35 patients.
abstract: Few data are available on serum free thyroid hormone concentration in patients with T3-toxicosis. In this study total and free T4 and T3 and TBG were evaluated in 35 subjects with T3-toxicosis, including 12 with untreated Graves' disease, 5 Graves' patients on methimazole treatment, 13 with autonomous adenoma, 3 with multinodular goiter, and 2 with subacute thyroiditis. T4, T3, free T4 (FT4), free T3 (FT3) as well as calculated T4/TBG and T3/TBG ratios were significantly higher in patients than in 37 healthy controls. Serum FT4 levels above the normal range were found in 19 subjects with T3-toxicosis (9 with untreated and one with methimazole-treated Graves' disease, 6 with autonomous adenoma, 1 with multinodular goiter and 2 with subacute thyroiditis). These data, together with the few previous reports, indicate that high FT4 levels are present in about half of the patients with so called T3-toxicosis, and that this occurs more frequently in diffuse than nodular goiter. It is suggested that the term T3-toxicosis be used only for those subjects with normal total and free T4.
mesh_terms: D006111:Graves Disease / Q000097:blood; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood*; D013960:Thyroid Function Tests; D013963:Thyroid Hormones / Q000097:blood*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D013963:Thyroid Hormones; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine