Thyroid Peroxidase Signs & Symptoms

Thyroid peroxidase antibodies are elements of the immune system that mistakenly damage the thyroid gland. The presence of these antibodies, and their symptoms, mirror those of two underlying causes of thyroid disease.


Thyroid peroxidase (TPO) is an enzyme of the thyroid gland that assists in the production of thyroid hormone. A thyroid peroxidase test determines the amount of bloodstream antibodies attacking TPO and reducing their ability to work.


Thyroid Peroxidase Signs & Symptoms

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According to endocrinologist Dr. Todd Nippoldt of the Mayo Clinic, the presence of thyroid peroxidase antibodies indicates that an autoimmune disorder, such as Hashimoto's disease or Graves' disease, is the probable cause of the thyroid problem itself. Autoimmune disorders come into play as the immune system mistakenly produces antibodies that attack and destroy healthy thyroid cells.


The first sign is typically a goiter (an enlarged thyroid or a lump of cells, also called a nodule) that swells to such an extent that it becomes visible through skin above the throat. Doctors will order a TPO antibody test when other results measuring the levels of the T3 or T4 hormone or TSH (thyroid stimulating hormone) show insufficient levels of these hormones.


L-Carnitine & Hypothyroidism

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Thyroid peroxidase signs and symptoms indicating high levels of damaging antibodies include constipation, difficulty concentrating, dry skin, neck swelling, fatigue, hair loss, heavy or irregular periods, cold intolerance, weight gain, a swollen face and joint stiffness.

Non-Thyroid Disorders

Those with non-thyroid-related auto-immune conditions like lupus, rheumatoid arthritis, or pernicious anemia may also display thyroid peroxidase signs and symptoms. Women with these disorders, especially when they become pregnant, should be closely monitored.