Thyroid Peroxidase Antibodies (TPOAb)
- Sample Type
- Serum
- Fasting
- No
- Unit
- IU/mL
Function
Thyroid Peroxidase (TPO) is an enzyme normally found in the thyroid gland that plays a crucial role in the production of thyroid hormones. The TPO Antibody test detects antibodies that the body's immune system mistakenly produces against this enzyme. These antibodies lead to inflammation and destruction of thyroid tissue.
Why it is Ordered
This test is ordered when a patient has abnormal TSH or T4 levels to determine if the cause is autoimmune. It is the hallmark test for diagnosing Hashimoto's thyroiditis (the leading cause of hypothyroidism) and is also found in Graves' disease. It may also be ordered for pregnant women with thyroid disease to assess the risk of postpartum thyroiditis.
Associated Conditions
- Hashimoto's Thyroiditis: Chronic autoimmune thyroiditis causing an underactive thyroid.
- Graves' Disease: Autoimmune hyperthyroidism.
- Postpartum Thyroiditis: Thyroid dysfunction occurring after childbirth.
- Other Autoimmune Disorders: Patients with Type 1 Diabetes or Rheumatoid Arthritis may show elevated TPOAb even without active thyroid disease.
Check Your Result
Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
The presence of TPO antibodies does not always mean a person has or will develop thyroid disease; a small percentage of the healthy population tests positive without symptoms. Conversely, antibody levels can fluctuate over time. It is crucial to correlate these results with thyroid function tests (TSH/FT4) and clinical symptoms rather than treating the antibody level itself.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for Thyroid Peroxidase Antibodies (TPOAb):
Official Sources
- Hashimoto Thyroiditis - StatPearls - NCBI Bookshelfncbi.nlm.nih.gov
Research & Guidelines
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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