Thyroid Peroxidase Test

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What is thyroid peroxidase?

Thyroid peroxidase (TPO) is an enzyme made in the thyroid gland that is important in the production of thyroid hormone. TPO is found in thyroid follicle cells where it converts the thyroid hormone T4 to T3.

The thyroid gland is located in the lower part of the neck, below the Adam's apple, wrapped around the trachea (windpipe).

Picture of the thyroid gland
Picture of the thyroid gland

What is the thyroid peroxidase test?

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.

Medically Reviewed by a Doctor on 2/4/2014

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Thyroid Peroxidase Test - Diagnosis Question: Were you diagnosed with an autoimmune or other type of disorder from your thyroid peroxidase results? Please explain.