Thyroid Profile - used to evaluate thyroid gland function and to help diagnose thyroid disorders. The tests measure the amount of thyroid hormones in your blood. These hormones are chemical substances that travel through the bloodstream and control or regulate your body’s metabolism—how it functions and uses energy. Thyroxine or T4 and triiodothyronine or T3 are the two hormones produced by the thyroid gland and the levels of these hormones in the blood is what tells if your thyroid is working properly.