Your doctor can diagnose hyperthyroidism and hypothyroidism by testing the levels of thyroid hormones in your blood. Doctors measure hormones secreted by the thyroid itself, as well as thyroid-stimulating hormone (TSH), a chemical released by the pituitary gland that triggers hormone production in the thyroid.
When you are hypothyroid, higher quantities of TSH are circulating in your blood as your body attempts to increase production of thyroid hormones. The reverse is true with hyperthyroidism,...
It is not clear whether people who do not
have any risk factors and who do not have any symptoms of hyperthyroidism need
to be tested regularly for thyroid problems. The American Thyroid Association
recommends that adults, particularly women, be screened for thyroid problems
every 5 years, beginning at age 35. The U.S. Preventive Services Task Force
does not think there is enough evidence to recommend either for or against
regular thyroid testing. Talk to your doctor about whether you need to be
tested for thyroid problems.1, 2