Thyroid Peroxidase (TPO) Antibodies Test

The Thyroid Peroxidase (TPO) Antibodies test is a blood test that is used to help determine and differentiate between whether an individual has hypothyroidism (underactive thyroid) or thyroiditis (inflammation of the thyroid). The TPO test measures the level of an antibody that is directed against the enzyme thyroid peroxidase.

• An underactive thyroid is known as hypothyroidism. Hypothyroidism can cause symptoms of weight gain, tiredness, dry skin, constipation, the sensation of being too cold, and/or frequent menstrual periods.
• Inflammation of the thyroid is known as thyroiditis. An inflamed thyroid initially causes a leak of hormones that results in symptoms of an overactive thyroid, known as hyperthyroidism. Eventually the inflammation impairs thyroid hormone production resulting in underactivity, known as hypothyroidism. When symptoms occur, they may vary depending on the stage of inflammation.