Medical Diagnosis Exams

Thyroglobulin (Tg) is a glycoprotein with a molecular weight of approximately 660 kDa. Tg is synthesized in large quantities by the thyrocytes and released into the lumina of the thyroid follicles. Production of Tg is stimulated by TSH, intrathyroidal iodine deficiency and the presence of thyroid-stimulating immunoglobulins.

Tg plays a decisive role in the synthesis of the peripheral thyroid hormones T3 and T4. Elevated Tg concentrations have been reported in different thyroid conditions like Hashimoto’s disease, Graves’ disease, thyroid adenoma, and thyroid carcinoma.

The determination of Tg can also be helpful to distinguish between subacute thyroiditis and factitious thyrotoxicosis. In cases of congenital hypothyroidism the determination of Tg can be used to differentiate between the complete absence of the thyroid gland and thyroid hypoplasia or other pathological conditions.

The main application of Tg testing is the post‑operative follow‑up of patients with differentiated thyroid carcinoma (DTC).