Thyroid peroxidase antibodies (anti-TPO)

What it measures

Anti-TPO antibodies target a key enzyme in thyroid hormone synthesis. They indicate autoimmune thyroid disease and predict progression to hypothyroidism.

Specimen and preparation

• Specimen: Serum or lithium-heparin plasma
• Tube: Gold top

Reference range

Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.

Causes of high values

• Hashimoto thyroiditis
• Graves disease (often positive)
• Postpartum thyroiditis
• Low-titre positivity in healthy people, especially older women

Method

Chemiluminescent immunoassay

Good to know

Positive antibodies with subclinical hypothyroidism or in pregnancy increase the chance of treatment being needed.

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