Clinical Significance

Thyroid Peroxidase (TPO) is a membrane-bound heme protein with a molecular weight of approximately 100,000. TPO is involved in 2 different reactions in the biosynthesis of thyroid hormones. The presence of antibodies to thyroid peroxidase marks the presence of an accompanying impairment of thyroid function, or a potential impairment. With positive peroxidase antibodies, it suggests a thyroid disease possibly Hashimoto's thyroiditis.