The determination of TPO antibody levels is the most sensitive test for detecting autoimmune thyroid disease (eg, Hashimoto's thyroiditis, idiopathic myxedema, and Graves disease) and detectable concentrations of anti-TPO antibodies are observed in most patients with these disorders. The highest TPO antibody levels are observed in patients suffering from Hashimoto thyroiditis. In this disease, the prevalence of TPO antibodies is about 90% of cases, confirming the autoimmune origin of the disease. These autoantibodies also frequently occur (60%–80%) in the course of Graves disease.

This test measures thyroglobulin antibodies commonly present in patients with Hashimoto's thyroiditis. Antibodies against the protein thyroglobulin can result in the destruction of thyroid cells. This destruction can lead to hypothyroidism. NOTE: Dietary supplements containing biotin may interfere in assays and may skew results to be either falsely high or falsely low. For patients receiving the recommended daily doses of biotin, draw samples at least 8 hours following the last biotin supplementation. For patients on mega doses of biotin supplements, draw samples at least 72 hours following the last biotin supplementation.

These two tests measure antithyroglobulin antibodies and Anti-TPO antibodies that are commonly present in patients with Hashimoto's thyroiditis, Graves disease and other thyroid-related conditions. Antibodies against the protein thyroglobulin can result in the destruction of thyroid cells. TPO antibodies are created when the immune system of a person targets by pure error elements of the thyroid gland or protein, leading to chronic thyroid inflammation, tissue damage, and damage to the thyroid function. Leaving this untreated may cause severe health issues.