Anti-Thyroglobulin Antibodies (Anti-Tg)
Also called: Anti-Tg, Anti-thyroglobulin antibodies, TgAb
Anti-Tg antibodies target thyroglobulin, the precursor protein of thyroid hormones. Complementary to anti-TPO for autoimmune thyroid disease, and clinically critical for thyroid-cancer follow-up.
Published: Updated:
Check your result
Calculated in your browser - the number is not sent anywhere.
Have the whole report? Upload it - we'll explain every value on it
What does Anti-Thyroglobulin Antibodies (Anti-Tg) measure?
Thyroglobulin is a large protein produced exclusively by the thyroid gland and used as the precursor for T3/T4 synthesis. In autoimmune thyroid disease the immune system can target it directly. Anti-Tg is positive in ~70% of Hashimoto's and ~30% of Graves', usually alongside anti-TPO. The clinically critical role is in differentiated thyroid-cancer follow-up: after thyroidectomy + radioiodine, thyroglobulin itself should be undetectable, so any rise signals recurrence — BUT the presence of anti-Tg antibodies interferes with the assay and can falsely lower the result. Hence anti-Tg is always measured alongside thyroglobulin in cancer surveillance.
What does a high Anti-Thyroglobulin Antibodies (Anti-Tg) level mean?
- Autoimmune thyroid disease — Hashimoto's, Graves' (often together with anti-TPO).
- Thyroid cancer follow-up — interferes with thyroglobulin tumour-marker assay; rising titre can independently signal recurrence.
- General autoimmune predisposition — low-positive in some healthy individuals, especially women.
What does a low Anti-Thyroglobulin Antibodies (Anti-Tg) level mean?
- Generally favourable. Negative result in a previously-treated thyroid-cancer patient simplifies thyroglobulin monitoring.
When to discuss with a doctor
Anti-Tg alone rarely changes management. It is most actionable in two contexts: (a) confirming the autoimmune nature of overt thyroid disease when anti-TPO is negative; (b) interpreting thyroglobulin in differentiated thyroid-cancer surveillance — your oncology / endocrine team handles this. Mediora.AI shows the full thyroid antibody picture; cancer surveillance is specialist territory.