Thyroid Antibodies (TPO and Tg)

Antibodies against thyroid tissue, both thyroid peroxidase and thyroglobulin. They answer whether the immune system is involved, which is a different question from how much hormone is present.

Thyroid Antibodies in the Biomarker Guide — what it is, why it is tested, and what moves the number.

Add-on markers can only be added to venous samples.

Timing

No fasting needed and no particular time of day. Antibody levels do not swing about the way TSH does. Stop high-dose biotin 48 hours beforehand, because it interferes with the assay.

Turnaround: the lab reports this test within 24 hours of receiving your sample, counted in working days. Most samples reach them within about 3 days of posting. Full detail on our Turnaround Times page.

We do not interpret results. Not medical advice or a diagnosis.