Thyroglobulin and Antithyroglobulin explained easy. TG and Anti -Tg; (TgAb) tests

Описание: Antithyroglobulin antibody, or Anti-TG test, measures, antibodies against protein called, thyroglobulin.
The protein thyroglobulin is found and produced by thyroid cells.
There is two important cases when thyroglobulin and or anti thyroglobulin is elevated.
First Is, thyroid inflammation, which can be sign of autoimmune thyroiditis, Graves disease or overactive thyroid, Hashimoto thyroiditis.
And second, important predictor of Thyroid cancer.

If anti thyroglobulin is elevated it requires additional imaging research.
Antithyroglobulin antibody test can also be useful to monitor thyroid cancer reoccurrence after thyroidectomy.
In some cases thyroglobulin can be negative it can be covered by anti thyroglobulin. So, antithyroglobulin can have surrogate value to estimate cancer reoccurrence.
There are controversial studies to define prognostic value of antithyroglobulin, in case of cancer reoccurrence monitoring.
According to some studies in excellent cases: anti thyroglobulin should lower over 6 months after cancer treatment (after, thyroidectomy and radioactive iodine treatment ).
And in around 3 year it should be negative.
But many cases it stays stable or elevated.
Important elevation of anti thyroglobulin means elevation more then 50 % after initial or last measurement.
And important reduction is if its level lowers more then 50% . in perfect cases it becomes negative.
To summarize:
If anti thyroglobulin is elevated additional studies are required to assess thyroid function and structure.
If anti thyroglobulin is used for observation of cancer reoccurrence , in case of important elevation, additional imagine studies are required.
Stable level of anti TG also may requires further studies.
And persistent negative anti TG has excellent prognosis.
By CFCF - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index...
By Nevit Dilmen (talk) - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index...