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Anti-Thyroglobulin (Anti-Tg) Unit Converter
Anti-Thyroglobulin Antibodies (Anti-Tg) are autoantibodies directed against thyroglobulin, a major protein produced by the thyroid gland used for producing thyroid hormones (T3 and T4). The presence of these antibodies is a hallmark of autoimmune thyroid diseases, such as Hashimoto’s thyroiditis and Graves’ disease.
Beyond diagnosis, measuring Anti-Tg is critical in the management of Differentiated Thyroid Cancer. After a thyroidectomy, serum Thyroglobulin (Tg) levels are monitored to detect cancer recurrence. However, the presence of Anti-Tg antibodies can interfere with Tg immunoassays, causing falsely low results (masking the cancer). Therefore, Anti-Tg is always measured alongside Tg. 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-Tg is detected in 60-70% of patients with Hashimoto’s thyroiditis and about 30% of patients with Graves’ disease. However, the Anti-TPO antibody is generally considered a more sensitive marker for autoimmune thyroiditis.
The most vital role of Anti-Tg is as a surrogate marker or interference flag in thyroid cancer monitoring. Even in patients with undetectable Thyroglobulin, a rising Anti-Tg trend can suggest tumor recurrence (the immune system reacting to new thyroid tissue). Reference ranges vary by assay but are often < 20 IU/mL or < 115 IU/mL depending on the manufacturer.
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-Tg is a heterogeneous mixture of antibodies. We measure binding activity (International Units), not mass.
Yes, in the context of Anti-Tg assays standardized to WHO reference materials, U/mL and IU/mL are used interchangeably.