What is Tri Iodothyronine (T3) test?
Insufficient production of thyroid hormones T3 and T4 is known as hypothyroidism and overproduction is termed as hyperthyroidism or thyrotoxicosis. Estimation of Serum TSH along with T3 and T4 is useful for differentiating the primary thyroid disorders (from thyroid gland) from secondary thyroid disorders (from the pituitary gland). In primary hypothyroidism, TSH level is elevated but in secondary hypothyroidism, the TSH level is low.
Why get the Tri Iodothyronine (T3) test?
Estimation of T4 (thyroxine) and T3 (triiodothyronine) is the mainstay of the diagnosis of thyroid diseases. Both are decreased in hypothyroidism but increased in hyperthyroidism. When the results of T4 and T3 are borderline, free hormone levels FT3 and FT4 are estimated.
When to take this test?
AnytimeEvery 6 monthsNo particular precautions are required, unless it is recommended by your doctor.T3