TPO Test - More Information

The TPO test, also known as a TPO blood test, thyroid peroxidase antibody, TPO antibody test, and TPO Ab test, measures the TPO antibody blood level.

Thyroid peroxidase, or thyroperoxidase (TPO), is an enzyme that is important in thyroid hormone production. When the immune system is overactive, it can produce special proteins called TPO antibodies which slow or stop TPO's activity. By blocking TPOs activity, TPO antibodies cause the thyroid gland to be underactive - a condition called hypothyroidism. One study suggests that higher TPO antibody levels may be correlated with disease severity. Because they are often present when hypothyroidism is diagnosed, TPO testing is often performed with the TSH test and as part of the hypothyroidism test panel.

TPO antibodies are also related to more specific thyroid conditions in which the thyroid gland is underactive. Two of those conditions are Graves' disease and Hashimoto's thyroiditis. As a result, TPO blood testing is also performed as part of the Hashimoto's test panel.

To get a TPO test near you, simply order online and get your blood drawn at the Quest Diagnostics lab. Once your TPO lab results are ready, they will be available for download. As can be seen on the sample TPO lab report, the TPO blood levels are reported as a numerical value and can be compared against the reference range provided by the lab.