- Triiodothyronine Replacement
- Thyroid Function Test
- Thyroid Function Summary
- Thyroid Anatomy
- Thyroxine (Free T4)
- Thyroid Stimulating Hormone (TSH)
- Free Thyroxine Index (Free T4 Index)
- Thyroxine Binding Globulin (TBG)
- Thyroid Releasing Hormone (TRH)
- Antithyroid Antibody
- Thyroxine Replacement
- Hypothyroidism
- Hyperthyroidism
- Hypothyroidism in Pregnancy
- Thyroid Dysfunction in Pregnancy
- See Thyroid Anatomy
- Images
- Normal Levels
- Triiodothyronine (T3): 80-180 ng/dl
- Free T3: 230-619 pg/dl
- Measurement
- T3 radioimmunoassay measures bound and Free T3
- Affected by TBG levels as well as other factors
- Free Triiodothyronine (Free T3) measures only active T3
- Not affected by Thyroid Binding Globulin (TBG)
- Represents 0.3% of total T3
- False Hypothyroidism if impaired T4 to T3 conversion
- Systemic illness
- Fasting
- Surgical stress
- Drugs
- Prednisone
- Propylthiouracil
- Amiodarone
- Radiopaque contrast
- Propranolol