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.
When an individual has hyperthyroidism, the thyroid gland makes too much thyroxine, Mayo Clinic explains. This problem increases the metabolism, leading to sudden weight loss, irregular heartbeat, sweating and nervousness. The specific treatment for hyperthyroidism depends upon a patient's age, general health and the seriousness of the condition.
Drug options include radioactive iodine, which shrinks the thyroid gland, states Mayo Clinic. Anti-thyroid medications prevent the thyroid from manufacturing extra hormones. In certain cases, a surgeon removes most of the malfunctioning thyroid.