High free triiodothyronine 6.89 pmol/L may be Graves’ disease, subacute thyroiditis, laboratory error, etc. If it is Graves’ disease, treatment is needed. 1. Graves’ disease: it is an autoimmune thyroid disease, there may be high free triiodothyronine, decreased thyroid stimulating hormone, positive TRAB antibody, need to consider taking antithyroid medication, such as methimazole, propylthiouracil, etc., and iodine radiation therapy may also be considered. 2. Subacute thyroiditis: it is a self-limiting disease, free triiodothyronine can be high in hyperthyroidism, but the disease can be relieved by itself to a certain extent. 3. Laboratory error: If only free T3 is mildly elevated, but free T4, total T3, total T4, and TSH levels are normal, this may be a laboratory error and can be reviewed periodically. In case of high free triiodothyronine, it is recommended to go to the hospital and ask the doctor to make comprehensive considerations according to your own situation, and it is not advisable to make blind judgments on your own.