More info
Thyroglobulin (Tg) is a 660 kDa, dimeric protein produced by the follicular cells of the thyroid and used entirely within the thyroid gland. Thyroglobulin protein accounts for approximately half of the protein content of the thyroid gland. Metabolism of thyroglobulin occurs in the liver and via thyroid gland recycling of the protein. In the clinical laboratory, thyroglobulin testing can be complicated by the presence of anti-thyroglobulin antibodies (ATA), frequently referred to as TgAb. Thyroglobulin antibodies are present in 1 in 10 normal individuals and a greater percentage of patients with thyroid carcinoma. The presence of these antibodies can result in falsely low (or rarely falsely high) levels on thyroglobulin testing. In patients with anti-thyroglobulin antibodies, a better strategy is to not rely on any single lab result but instead to follow serial quantitative measurements.