Anti-thyroglobulin antibodies
What it measures, and what changes the number.
Anti-thyroglobulin antibodies are proteins made by the immune system that target thyroglobulin, a protein produced by the thyroid gland and used to build thyroid hormones. The test measures how much of this antibody is circulating in the blood.
It is usually ordered with anti-TPO antibodies, the other main thyroid autoantibody, and with TSH and free thyroid hormones, so the immune findings can be read next to how the gland is working. In people followed after thyroid cancer treatment it is also checked whenever thyroglobulin itself is measured, because these antibodies can interfere with that measurement.
Fasting and time of day have little effect. Different immunoassay methods give results that are not directly comparable, so results are best followed on the same lab and method over time. Reports may list it as Ac. anti Tiroglobulina.
Often read alongside: Anti-TPO antibodies, TSH, Free T4, Free T3