What is TPO antibodies?
autoimmune attack on your thyroid
TPO antibodies indicate autoimmune thyroid disease (most often Hashimoto's). They often appear before TSH becomes abnormal and explain many cases of low-grade thyroid dysfunction.
TPO is an enzyme needed to make thyroid hormones. Antibodies against it disrupt production and often lead, over time, to underactive thyroid.
Test facts
- Unit
- kIE/L
- Sample
- Serum
- Fasting
- No fasting needed
- Turnaround
- 3 days
What does low TPO antibodies mean?
Negative TPO antibodies make autoimmune thyroid disease less likely.
What does high TPO antibodies mean?
Positive TPO antibodies suggest autoimmune thyroid disease. The risk of developing hypothyroidism over time is increased.
Panels that measure TPO antibodies
- Hormone+
- Pre-Conception
- Thyroid Complete
- Thyroid + Autoimmune
More markers in the same area
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This is general information about the marker, not an assessment of your values and not medical advice. Last updated: May 2026.