AntiThyreoglobulin

AntiThyreoglobulin, also known as anti-thyroglobulin antibodies (TgAb), are autoantibodies directed against thyroglobulin, the protein precursor of thyroid hormones. They are commonly found in autoimmune thyroid diseases, particularly Hashimoto's thyroiditis, and can occur with anti-thyroid peroxidase antibodies, though TgAb may also appear alone. TgAb can be detected in the blood using immunoassays such as ELISA or chemiluminescent assays, with results reported as qualitative positive/negative or as a titer.

Clinical significance and interpretation: The presence of TgAb supports the diagnosis of autoimmune thyroid disease in the appropriate clinical context but is not disease-specific. TgAb can be found in a subset of healthy individuals and in other autoimmune conditions. In the management of thyroid cancer, TgAb can complicate surveillance because antibodies against thyroglobulin may interfere with immunoassays used to measure thyroglobulin, potentially causing falsely low or high results. For patients with TgAb, clinicians may rely on alternative monitoring strategies, such as imaging, or use assays less affected by TgAb. Serial TgAb measurements can sometimes aid in monitoring disease activity in conjunction with thyroglobulin results and imaging, though their utility varies by assay and clinical scenario.

Management: There is no specific treatment to remove TgAb; treatment decisions focus on the underlying thyroid condition. TgAb testing remains a tool for diagnosis and, in some cases, for monitoring in conjunction with other clinical and laboratory data.