Anti Thyroid Peroxidase (Anti-TPO)

High thyroid peroxidase (TPO) antibodies indicate an autoimmune attack on the thyroid—most commonly Hashimoto’s thyroiditis, less often Graves’ disease. Elevated TPO raises the risk of thyroid dysfunction, typically leading to hypothyroidism or fluctuating thyroid levels. It can appear before symptoms and warrants monitoring with TSH and free T4 and discussion with a clinician for diagnosis, follow‑up, and treatment planning.

Low anti‑TPO antibodies (undetectable or low titers) generally indicate a low likelihood of autoimmune thyroid disease. This often corresponds with normal thyroid function, but clinical assessment and thyroid hormone tests (TSH, free T4/T3) matter. Low anti‑TPO itself rarely causes problems; repeat testing or follow‑up may be recommended if symptoms or abnormal thyroid function appear.

Normal anti‑thyroid peroxidase (anti‑TPO) antibody levels in pregnancy are below the laboratory’s reference cutoff; commonly a negative result is <35 IU/mL. Some labs use thresholds up to 60 IU/mL, so interpretation depends on the assay and pregnancy stage. Positive anti‑TPO above the lab reference range should be discussed with your clinician for monitoring and management.

High TPO antibodies signify autoimmune thyroid disease. Treatment focuses on monitoring thyroid function and treating hypothyroidism with levothyroxine when indicated. Selenium supplementation may modestly lower antibody levels in some people, but discuss risks with your clinician. Manage symptoms, avoid smoking, maintain balanced iodine intake, screen for other autoimmune conditions, and monitor closely during pregnancy. Immunosuppressive therapy is not routinely used.

High TPO antibodies reflect autoimmune thyroid disease and are not usually "curable." Management focuses on treating thyroid dysfunction (e.g., levothyroxine if hypothyroid), monitoring, and symptom control. Antibody levels may fall in some people or with specific treatments, but autoimmune activity often persists long-term. Regular follow-up and individualized therapy can stabilize thyroid function and reduce symptoms.

The first stage of Hashimoto’s is the early autoimmune phase, when the immune system makes anti-thyroid peroxidase (anti‑TPO) antibodies and begins attacking the thyroid. Many people are asymptomatic with normal thyroid hormone levels or have subtle signs; some experience a brief hyperthyroid (hormone‑leak) phase. Over time, continuing damage leads to declining thyroid function and rising TSH, causing overt hypothyroidism.