Thyroglobulin antibodies (commonly abbreviated TgAb or TGA) are auto‑immune proteins produced by the immune system that mistakenly target thyroglobulin, a large glycoprotein stored in the thyroid gland. Thyroglobulin serves as the scaffold for the synthesis and storage of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). When the immune system generates antibodies against this protein, it can interfere with normal thyroid function and is a hallmark of several autoimmune thyroid disorders.