FT3 test

Triiodothyronine FT3 test

It is one of the main thyroid hormones. Its action is essential for the proper functioning of the body.

The hormones FT3 (triiodothyronine) and FT4 (thyroxine) are hormones produced by the thyroid gland. They control the functions of most organs, support metabolic processes and the function of the central nervous system. The thyroid gland produces mainly (85%) thyroxine (FT3) Triiodothyronine is also produced by the thyroid gland, but about 80% comes from the metabolism (conversion) of thyroxine, which occurs in the body's cells of the body. The remainder is secreted directly by the thyroid gland.

The concentration of FT3 is determined for the specific diagnosis of diseases of the of the thyroid gland.

The main indication for its performance is suspected hyperthyroidism, when a low TSH concentration is accompanied by a normal FT4 concentration. It is not recommended to determine triiodothyronine in order to adjust thyroxine dosage in patients with hypothyroidism.

The determination of FT4 concentrations is more authoritative than the determination of FT3 because triiodothyronine concentrations depend primarily on non-thyroid factors.

FT3 action

Functions of the triiodothyronine hormone FT3:

• regulation of metabolism
• supporting the development of the nervous system in newborns
• support of the cardiovascular system

Thyroid hormones are essential for the body to function properly of the body, which is why diagnosing suspected diseases of this gland is very important.

An elevated concentration of the FT3 hormone with a concomitant concentration of TSH below normal may indicate hyperthyroidism. Low FT3 with an elevated TSH concentration can be a sign of hypothyroidism thyroid gland.