How do you manage patients with mildly elevated free T4 levels but normal TSH and Total T3 levels who have symptoms of hyperthyroidism but negative Graves' antibodies and normal pituitary imaging?

I would make sure to double check the accuracy of the free T4 assay/measurement. If it is very mildly high (0.1 ng/dl higher than ULN) might be an assay issue, but if it is 1.5-2x ULN, then maybe a real elevation. I would make sure the patient is not on high-dose biotin or any other interfering medi...