Thyroid function test Triiodothyronine (T₃): 80 to 230 ng/dLThyroxine (T₄): 5 to 12 mcg/dLThyroxine, free (FT₄): 0.8 to 2.4 ng/dLThyroid-stimulating hormone (thyrotropin): 0.2 to 5.4 microunits/mL