T4 Thyroxine

The T4 (Thyroxine), Total test is a blood test that helps doctors find out if a person has thyroid problems. The thyroid is a small gland in your neck that makes hormones to help your body use energy. This test measures how much thyroxine (a thyroid hormone) is in your blood. Doctors use this test to check if the thyroid is making too much hormone (which is called hyperthyroidism) or not enough hormone (which is called hypothyroidism). Knowing this helps doctors treat thyroid problems better.