What Does High FT4 and Low TSH Mean?

By Staff WriterLast Updated Mar 24, 2020 7:40:21 PM ET

A person who has high FT4 test results and low TSH results has hyperthyroidism, according to the American Thyroid Association. FT4 looks for thyroxine, the primary thyroid hormone. A TSH test measures the amount of thyroid stimulating hormone that the pituitary gland releases into the blood.