Anti-TG (Thyroglobulin Antibodies) is a blood test that measures anti-tg (thyroglobulin antibodies) levels in the blood. Normal range: A negative result (commonly below 40 IU/mL, though the cut-off varies by lab and assay) is normal. The result is usually reported as positive or negative rather than as a precise level. A small number of healthy people carry low-level antibodies without thyroid disease.. It is commonly used to detects autoimmune thyroid conditions like Hashimoto's thyroiditis, often before thyroid hormone levels change..
What is Anti-TG (Thyroglobulin Antibodies)?
Antibodies targeting thyroglobulin, a protein essential for thyroid hormone production.
Why is it measured?
Detects autoimmune thyroid conditions like Hashimoto's thyroiditis, often before thyroid hormone levels change.
Normal Reference Range
A negative result (commonly below 40 IU/mL, though the cut-off varies by lab and assay) is normal. The result is usually reported as positive or negative rather than as a precise level. A small number of healthy people carry low-level antibodies without thyroid disease.
Note: Reference ranges may vary between laboratories. Always consult your healthcare provider for interpretation.
What Causes High ANTI?
Raised thyroglobulin antibodies indicate the immune system is targeting the thyroid. The most common cause is Hashimoto's thyroiditis (autoimmune hypothyroidism), and they are also seen in Graves' disease and other autoimmune conditions such as type 1 diabetes and coeliac disease. In people treated for thyroid cancer, anti-TG antibodies are tracked because they interfere with thyroglobulin tumour-marker monitoring. Antibodies can be present years before thyroid hormone levels become abnormal.
What Causes Low ANTI?
A low or negative result is the normal, reassuring finding and means no detectable thyroid autoimmunity. No clinical action is needed for a negative result.
How Often Should ANTI Be Tested?
Anti-TG is usually a one-off test when autoimmune thyroid disease is suspected — for example, an abnormal TSH, a goitre, or unexplained thyroid symptoms — typically ordered together with anti-TPO antibodies. It is not part of routine screening and rarely needs repeating once a diagnosis is established.
Related Blood Markers
Interpreted alongside TSH, free T4, and especially anti-TPO antibodies (the more sensitive marker for Hashimoto's). In Graves' disease, TSH-receptor antibodies (TRAb) are the key confirmatory test.
Key Facts
- •Category: Hormone Health
- •Unit of Measurement: IU/mL
- •Test Code: ANTI_TG
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