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Anti-TPO Antibody Unit Converter
Anti-Thyroid Peroxidase (Anti-TPO) antibodies are autoantibodies directed against the thyroid peroxidase enzyme. This enzyme, located in the thyroid follicles, is essential for the iodination of tyrosine residues in thyroglobulin during the synthesis of thyroid hormones (T3 and T4).
Clinically, Anti-TPO is the most sensitive serological marker for autoimmune thyroid disease. It is present in over 90% of patients with Hashimoto’s thyroiditis (chronic lymphocytic thyroiditis), the leading cause of hypothyroidism, and in about 75% of patients with Graves’ disease. Testing is also crucial for assessing the risk of postpartum thyroiditis and for investigating subclinical hypothyroidism. Results are reported in International Units (IU/mL or kIU/L). This converter ensures consistency between these reporting standards.
SI Units
RecommendedKilo-International Units per liter.
Conventional Units
Clinical Context
Anti-TPO was historically known as the “anti-microsomal antibody.” Modern immunoassays are far more specific. The presence of Anti-TPO confirms the autoimmune nature of thyroid dysfunction. In pregnant women, high titers are a risk factor for miscarriage and postpartum thyroid dysfunction.
Reference ranges depend heavily on the assay platform but are typically < 35 IU/mL or < 9 IU/mL. Values in the thousands are common in active Hashimoto’s. Since 1 IU/mL = 1 kIU/L, conversion is straightforward but essential for data harmonization.
Clinical References
How to Use This Calculator
Follow these steps to get accurate clinical conversions instantly.
Enter Values
Input your laboratory results into the corresponding unit field (e.g., IU/mL). You can use either dot or comma decimals.
Automatic Conversion
The calculator works in real-time. As you type in one field, all other units (like kIU/L) are instantly updated.
Verify Units
Check the SI Units section. Note that IU/mL and kIU/L are numerically identical.
Reset
Use the Clear button to reset all fields before starting a new calculation.
Frequently Asked Questions & Tips
Anti-TPO is an antibody. We measure its activity/binding capacity in International Units, not its mass.
Yes, in the context of Anti-TPO, these terms are used interchangeably for the same international standard.