What Does a High Level of Thyroid Peroxidase Mean?

Universal Images Group Editorial/Universal Images Group/Getty Images

High levels of thyroid peroxidase enzyme are indicative of a thyroid autoimmune disorder, such as Hashimoto’s or Graves’ disease. High levels are caused by thyroid peroxidase antibodies, as stated by Lab Tests Online.

Thyroid peroxidase is an enzyme produced by the thyroid gland, which is situated in the neck, reports MedicineNet. Thyroid hormones regulate various functions in the body such as metabolism, protein synthesis and growth. The enzyme works to convert thyroid hormone to thyroxine and triiodothyronine, the active forms of the hormone. A thyroid peroxidase antibody test measures the level of the enzyme.

Autoantibodies damage the thyroid gland and cause thyroid disease. The test is among the thyroid function tests recommended by physicians for individuals suspected of thyroid gland abnormality. Graves’ disease is an autoimmune disorder caused by hyperthyroidism. Hashimoto’s thyroiditis often leads to hypothyroidism, as stated by Mayo Clinic.

High levels of the enzyme can also indicate nonthyroid autoimmune-related conditions such as systematic lupus erythematosus, rheumatoid arthritis, Type 1 diabetes or pernicious anemia. Other individuals may show a positive test but have no symptoms of thyroid disease yet have an increased risk of future thyroid disease. Females have higher chances of a positive thyroid peroxidase antibody test, as noted by MedicineNet.