Thyroglobulin Antibody
Also written as: TgAb — Thyroglobulin Antibody
An autoantibody directed against thyroglobulin that can interfere with thyroglobulin measurements and indicates autoimmune thyroid disease.
Full Definition
Thyroglobulin antibody (TgAb) is an autoantibody that targets thyroglobulin, the protein precursor to thyroid hormones. These antibodies are found in approximately 10% of healthy individuals but are more prevalent in autoimmune thyroid conditions like Hashimoto's thyroiditis and Graves' disease. Clinically, TgAb serves two important purposes: as a marker of autoimmune thyroid disease and as an indicator of potential interference in thyroglobulin assays. When TgAb is present, thyroglobulin measurements may be falsely low or undetectable, which is particularly problematic in thyroid cancer monitoring where thyroglobulin serves as a tumor marker. Many laboratories now routinely measure TgAb alongside thyroglobulin to identify potential assay interference.
Usage
Usage note: Always consider TgAb status when interpreting thyroglobulin results in thyroid cancer patients.
In Context
- "Elevated thyroglobulin antibody levels indicated potential interference with the thyroglobulin tumor marker assay." — Thyroid cancer follow-up report
- "The presence of TgAb necessitated alternative monitoring strategies for this post-thyroidectomy patient." — Endocrinology consultation