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Anti-TPO (Thyroid Peroxidase Antibody) Test

✅ Up to date🔬 Evidence: StrongEndocrine & Metabolism
Diğer adları: Thyroid peroxidase antibody, TPOAb, TPO antibody
⚠️

Discuss your test results with your doctor. This page is for informational purposes only and does not provide a diagnosis.

⚡ Key Facts

• Measures autoantibodies against thyroid peroxidase enzyme • The most common marker for autoimmune thyroid disease • Positive in most Hashimoto's thyroiditis and many Graves' disease cases • A positive result does not always mean thyroid dysfunction is present

🧪 What Does This Test Measure?

The anti-TPO test measures autoantibodies against the thyroid peroxidase enzyme, serving as the most common marker for autoimmune thyroid disease.

📋 Why Is It Ordered?

Ordered for autoimmune thyroid disease evaluation, investigating the cause of hypothyroidism, and assessing progression risk in subclinical thyroid disease.

🔧 Preparation

No special preparation is required. Fasting is not necessary and the test can be performed at any time of day.

📊 Reference Ranges

Negative (normal): generally <35 IU/mL (varies by laboratory) Positive: above the laboratory's established threshold ⚠️ Thresholds and units vary significantly between laboratories and assay methods.

⬆️ High Values

Positive anti-TPO may be associated with Hashimoto's thyroiditis, Graves' disease, or other autoimmune conditions. A positive result does not always indicate current thyroid dysfunction.

⬇️ Low Values

A negative anti-TPO result reduces the likelihood of autoimmune thyroid disease; however, in rare cases, antibody-negative autoimmune thyroiditis can occur.

⚙️ What Can Affect Results?

Age, sex, genetic predisposition, iodine intake, other autoimmune diseases, and assay method may affect anti-TPO results.

🔬 Evidence Summary

Strong evidence: 3 guidelines, 1 systematic review, 2 reviews, 2 observational studies.

✅ Key Takeaways

💡

What you learned: Anti-TPO is the primary marker for autoimmune thyroid disease. A positive result indicates immune activity against the thyroid but does not always mean thyroid dysfunction.

⛔

A positive anti-TPO result alone does not diagnose thyroid disease. TSH, clinical findings, and follow-up are needed.

🔬 Sources Used on This Page

9 sources · Most recent publication: 2023
📋
Guideline
Expert society and guideline recommendations
3
sources
📊
Systematic review / meta-analysis
Combined analysis of multiple studies
1
source
📖
Review
Comprehensive topic evaluation
3
sources
👁
Observational
Observational and cohort studies
2
sources
Overall assessment: Evidence level for this topic is strong. This page is supported by 3 guidelines, 1 systematic review/meta-analysis, 3 reviews, 2 observational studies.

📝 Questions to Ask Your Doctor

Be prepared for your appointment. Add questions to your list.

Last reviewed: 3/31/2026
Next review: 6/30/2026

🔗 Related Topics

🩺 Hipotiroidizm🩺 Hipertiroidizm🧪 TSH (Tiroid uyarıcı hormon)🧪 Serbest T4 (sT4)🧪 Serbest T3 (sT3)
⚖️ This page does not replace medical advice. Make treatment decisions with your doctor.
Content is based on scientific studies indexed in PubMed and current clinical guidelines.