What's the reference range for the Free T4? Ranges vary from lab to lab so have to come from your own lab report.
Also, what if any, symptoms do you have? Are you currently on a replacement thyroid hormone medication? If so, what medication/dosage and how long have you been on it?
Do you have any symptoms that could be attributed to, either, hyper or hypothyroidism?
Have you ever had thyroid antibodies done to determine if you have an autoimmune thyroid condition - either Hashimoto's Thyroiditis or Graves Disease?
Hashimoto's is, typically, associated with hypothyroidism, but early stages can be characterized by periods of hyper, alternating with periods of normal or hypo. Graves Disease is always associated with hyperthyroidism.
Antibody tests for Hashimoto's are Thyroid Peroxidase Antibodies (TPOab) and Thyroglobulin Antibodies (TgAb). The definitive test for Graves is Thyroid Stimulating Immunoglobulin (TSI).