Antibodies against thyroid peroxidase (TPO); the common autoimmune thyroid marker.
What it is
TPO antibodies are frequently measured with TSH and free thyroid hormones when autoimmune thyroid disease is considered.
Why it matters
Positivity raises likelihood of autoimmune thyroiditis but does not by itself set treatment.
This guide is educational only and cannot diagnose you. Discuss results, especially anything outside your laboratory’s reference interval, or that does not match how you feel, with a GP or other appropriately qualified clinician.
How it affects the body
Ongoing autoimmunity can gradually impair thyroid hormone production.
For athletes
Unexplained fatigue with menstrual change or cold intolerance still needs a proper thyroid work-up, not antibody results alone.
Related tests
Panels that include Thyroid peroxidase antibodies.
