THYROID PEROXIDASE ANTIBODIES (TPO)

ANTI-TPO; ANTI-THYROID MICROSOMAL ANTIBODY; TPO

Thyroid peroxidase (TPO) is a glycosylated heme-protein located in the apical membrane of the thyrocyte, where it catalyzes iodide oxidation and further incorporation in the thyroglobulin molecule. TPO shares sequence homology with lactoperoxidase, myeloperoxidase and eosinophil peroxidase. 

Thyroid peroxidase test is a test that measures the level of an antibody that is directed against thyroid peroxidase (TPO).

Autoantibodies to thyroid peroxidase (TPOAb) are produced within the body. The presence of TPOAb in the blood reflects a prior attack on the thyroid tissue by the body's immune system.

The presence of TPO antibodies in your blood suggests that the cause of thyroid disease is an autoimmune disorder, such as Hashimoto's disease or Graves' disease. In autoimmune disorders, your immune system makes antibodies that mistakenly attack normal tissue.