title: Letter: Comparison between free thyroxine index and effective thyroxine ratio.
mesh_terms: D006801:Humans; D006980:Hyperthyroidism / Q000097:blood; D009230:Myxedema / Q000097:blood; D013960:Thyroid Function Tests; D013974:Thyroxine / Q000097:blood*
chemical_list: D013974:Thyroxine