Thyroid peroxidase (TPO) is an enzyme essential for thyroid hormone synthesis.

Anti-TPO antibodies attack this enzyme, leading to thyroid gland inflammation and dysfunction.

Clinical uses include:

Diagnosing autoimmune thyroid diseases (Hashimoto’s thyroiditis, Graves’ disease).

Supporting evaluation of patients with hypothyroidism or hyperthyroidism.

Assessing risk of thyroid dysfunction in individuals with family history of autoimmune disease.

Monitoring disease progression and treatment response.

The test is performed using a blood sample.

Analyte: Anti-thyroid peroxidase antibodies in serum.

Normal Range: Negative (< 35 IU/mL; varies slightly by lab).

Abnormal Findings:

Positive Anti-TPO: Indicates autoimmune thyroid disease.

High titers: Stronger association with Hashimoto’s thyroiditis and risk of hypothyroidism.

Clinical Use:

Provides a specific marker for autoimmune thyroid disorders.

Helps differentiate thyroid disease causes.

Guides treatment and monitoring in endocrine practice.