A thyroxine test helps diagnose disorders of the thyroid. The thyroid is a small, butterfly-

shaped gland located near the throat. Your thyroid makes hormones that regulate the way

your body uses energy. It also plays an important role in regulating your weight, body

temperature, muscle strength, and even your mood. Thyroxine, also known as T4, is a type of

thyroid hormone. This test measures the level of T4 in your blood. Too much or too little T4

can indicate thyroid disease.