Only FT4 is elevated in the five items of thyroid function, which can be seen in normal people, drug effects, pituitary hyperthyroidism, etc. If only FT4 is mildly elevated, it may not be of great clinical significance, and it is recommended to review it regularly. 1. Normal people: if only FT4 is mildly elevated, it may not be of great clinical significance, and regular review is recommended. 2 drug effects: taking amiodarone leads to increased synthesis of thyroxine, or oral high-dose propranolol leads to peripheral T4 to T3 conversion is inhibited, manifested in only FT4 increase, after stopping the drug can be improved. 3. Pituitary hyperthyroidism: FT4 is elevated, TSH is not reduced, seen in pituitary hyperthyroidism (rare) or thyroid hormone resistance syndrome, need to be treated under the guidance of a doctor. Abnormal thyroid function, should be examined and treated under the guidance of a doctor.