The Anti-Thyroid Peroxidase Antibody (ATPO or TPOAb) test detects antibodies against thyroid peroxidase, an enzyme crucial for thyroid hormone production. This test is primarily used to diagnose autoimmune thyroid disorders, such as Hashimoto’s thyroiditis and Graves’ disease.

Preparation: No special preparation or fasting is required.

Procedure: A blood sample is drawn from a vein, usually in the arm.