The protein thyroglobulin (Tg) is the basic material for the synthesis of the thyroid hormones thyroxine and triiodothyronine. Thyroglobulin is only formed by the follicle cells of the thyroid gland. Healthy people show a very low concentration in the serum. Increased levels appear in inflammatory processes of the thyroid gland and in tumors.
The determination of Tg gains particular significance in the aftercare of patients whose thyroid gland was removed during the course of a tumor therapy. Without active thyroid tissue there is no Tg detectable in the serum of these patients. Already minor increase of Tg can be used as a marker for lingering or newly developing tumors.