Synonyms: Anti-thyroglobulin antibodies
Related tests: FT3, FT4, TSH, anti-peroxidase
Clinical significance
Anti-TG antibodies are circulating immunoglobulins directed against thyroglobulin, the main component of the colloid in the thyroid follicles, and are often present in autoimmune thyroid diseases (although less often than anti-thyroid peroxidase antibodies). They are found in people with autoimmune lymphocytic thyroiditis and in 40% of patients with Graves’ disease. They may sometimes also be present in subacute (De Quervain’s) thyroiditis.
Clinical indications
Autoimmune thyroiditis. Follow-up of differentiated thyroid cancer.
Sample type
The patient must have a blood sample taken.
Preparation
You must fast for at least 8 hours; a small amount of water is allowed. You must have been standing or sitting upright for at least 30 minutes.
Notes
The main use of the test is to confirm autoimmune thyroiditis, although it is less sensitive than anti-thyroid peroxidase (anti-TPO) antibodies.
Measuring anti-thyroglobulin antibodies is also essential when thyroglobulin is requested in differentiated thyroid cancer: the antibodies can make the thyroglobulin result inaccurate, as values may be underestimated.