The Tri-Iodothyronine Total (TT3) test is a blood test used to measure the levels of the hormone triiodothyronine (T3) in the body. T3 is produced by the thyroid gland and is involved in regulating metabolism, growth, and development. The TT3 test is often ordered along with other thyroid function tests to help diagnose thyroid disorders such as hyperthyroidism or hypothyroidism. Abnormal levels of T3 can indicate an overactive or underactive thyroid gland. The test involves drawing blood from a vein and the results are usually available within a few days. Your doctor will interpret the results and determine if any further testing or treatment is necessary.
