Thyroperoxidase Ab

Thyroperoxidase (TPO) antibodies are immune proteins that target the thyroid enzyme responsible for producing thyroid hormones. Elevated TPO antibody levels indicate autoimmune thyroid disease, most commonly Hashimoto's thyroiditis. This test is performed on serum or plasma and is one of the most important thyroid autoimmunity markers. High TPO antibody levels often precede thyroid dysfunction and predict progression to hypothyroidism. They are also associated with other autoimmune conditions and may affect fertility and pregnancy outcomes.