Anti-TPO
Anti-thyroid peroxidase antibodies (Anti-TPO) target the thyroid peroxidase enzyme, which is essential for thyroid hormone synthesis. These autoantibodies cause progressive destruction of thyroid tissue through immune-mediated inflammation. Anti-TPO is the hallmark antibody of Hashimoto's thyroiditis.
Why it matters: Anti-TPO antibodies are associated with autoimmune thyroid conditions such as Hashimoto's, and can be present even when TSH is still in range. Higher levels are commonly associated with greater thyroid involvement over time.
May increase with:
May decrease with:
What is Anti-TPO?
Anti-thyroid peroxidase antibodies (Anti-TPO) target the thyroid peroxidase enzyme, which is essential for thyroid hormone synthesis. These autoantibodies cause progressive destruction of thyroid tissue through immune-mediated inflammation. Anti-TPO is the hallmark antibody of Hashimoto's thyroiditis.
What might a high or low Anti-TPO mean?
Anti-TPO antibodies are associated with autoimmune thyroid conditions such as Hashimoto's, and can be present even when TSH is still in range. Higher levels are commonly associated with greater thyroid involvement over time.
What is the typical reference range for Anti-TPO?
The general-population reference range shown here is < 34 IU/mL. Reference ranges describe the general population and are not a personal target — discuss your results with your physician.
What can affect Anti-TPO?
It may be higher with: Hashimoto's thyroiditis (most common), Graves' disease (50-80% are also Anti-TPO positive), Other autoimmune conditions (type 1 diabetes, celiac), Family history of autoimmune thyroid disease, Post-partum thyroiditis, Iodine excess. It may be lower with: Selenium supplementation (200mcg/day — modest reduction in titers), Immunosuppressive therapy, Gluten-free diet (in celiac patients), Low-dose naltrexone (emerging evidence), Vitamin D optimization, Thyroid gland destruction (eventual burnout).