Anti-TPO Antibody Test
A blood test for thyroid antibodies that show autoimmune thyroid disease.
Quick Summary
To find the cause of hypothyroidism or thyroid swelling.
Thyroid peroxidase antibodies.
No preparation.
Overview
Positive antibodies suggest Hashimoto's thyroiditis.
They predict a higher chance of hypothyroidism later.
What It Measures
Anti-TPO
Antibody level.
How It's Performed
- 01
Preparation
Usually no special preparation unless your doctor advises.
- 02
Blood sample
A small amount of blood is taken from a vein in your arm.
- 03
Afterwards
Press on the spot; a small bruise is common.
Reference Ranges
Note: Normal ranges vary by laboratory. Consult your report for the specific reference used.
| Parameter | Typical Range (Adult) | Units |
|---|---|---|
| Anti-TPO | Below 35 | IU/mL |
Interpreting Results & Next Steps
Discuss with Doctor
Normal ranges differ between laboratories; use the range on your report. Your doctor will explain what your result means and what happens next.
If values are High:
Raised antibodies suggest autoimmune thyroid disease.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Thyroid Antibody Tests(opens in a new tab) · MedlinePlus, US National Library of Medicine