The thyroid gland produces a hormone, thyroxine, that helps regulate your metabolism. Metabolism is the process that turns food into energy, produces body heat and helps keep your body functions running smoothly. Your physician may order a thyroid test if he suspects you are having a thyroid problem, such as hypothyroidism or hyperthyroidism. Hypothyroidism occurs when the thyroid doesn't produce enough thyroxine. Your doctor may suspect this if you are experiencing symptoms such as abnormal drowsiness, weight gain, aching muscles, constipation, and dry skin.
Hyperthyroidism occurs when the thyroid produces too much thyroxine.
Your doctor may suspect this if you are experiencing symptoms such as weight loss, increased appetite, excessive sweating, heart palpitations, or vision trouble. A simple blood test can help your doctor determine whether you have a thyroid problem and need treatment.