A T4 test measures the blood level of the hormone T4, also known as thyroxine, which is produced by the thyroid gland and helps control metabolism and growth. TheT4 test is performed as part of an evaluation of thyroid function.
Triiodothyronine (T3) is one of two major hormones produced by the thyroid gland, a small butterfly-shaped organ that lies flat across the windpipe at the base of the throat. The other major thyroid hormone is called thyroxine (T4) and together they help control the rate at which the body uses energy. Almost all of the T3 (and T4) found in the blood is bound to protein. The rest is free (unbound) and is the biologically active…
TSH stands for thyroid stimulating hormone. A TSH test is a blood test that measures this hormone. The thyroid is a small, butterfly-shaped gland located near your 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. TSH is made in a gland in the brain called the pituitary. When thyroid levels in your body are low, the pituitary gland makes more TSH. When thyroid levels are high, the pituitary gland makes less TSH. TSH levels that are too high or too low can indicate your thyroid isn’t working correctly.
Other names: thyrotropin test