Anti Thyroid Peroxidase Antibodies (TPO)

The TPO (Thyroid Peroxidase) Antibody Test is a blood test that detects immune system proteins attacking the thyroid enzyme responsible for producing hormones. It is primarily used to diagnose autoimmune thyroid diseases like Hashimotos thyroiditis or Graves disease. A positive result suggests an autoimmune condition, often ordered if you have high TSH levels or symptoms like fatigue, weight gain, or swelling in the neck.