. Anti-Thyroid Peroxidaes Antibodies (Anti-TPO) are antibodies directed against thyroid peroxidase (TPO), an enzyme involved in the production of thyroid hormones in the thyroid gland.
. Anti-TPO is often associated with autoimmune thyroid diseases, particularly Hashimoto’s thyroiditis leading to hypothyroidism. Although anti-TPO antibodies are not the primary diagnostic marker for Graves' disease (which is more commonly diagnosed with TSI), they can be elevated in some cases, especially in patients with a coexisting autoimmune thyroiditis or those with longstanding Graves' disease.
. Anti-TPO can also be present in non-thyroid conditions e.g., other autoimmune diseases (Rheumatoid arthritis), Addison’s disease and Type I Diabetes.