Blood test
Thyroid Antibody Test
A thyroid antibody test looks for antibodies that attack the thyroid gland, helping to identify autoimmune thyroid disease.
Quick answer
Thyroid Antibody Test: what it is and what the results mean
Thyroid antibody tests measure antibodies such as thyroid peroxidase (TPO) and thyroglobulin antibodies, which are markers of autoimmune thyroid conditions where the immune system targets the thyroid gland.
- Why it is done: It is used to find out whether an underactive or overactive thyroid is caused by autoimmune disease (such as Hashimoto’s thyroiditis or Graves’ disease), and to assess the risk of thyroid problems developing, including in pregnancy.
- Understanding results: Raised thyroid antibodies suggest an autoimmune cause of thyroid dysfunction and a higher chance of ongoing thyroid problems.
What it is
Thyroid antibody tests measure antibodies such as thyroid peroxidase (TPO) and thyroglobulin antibodies, which are markers of autoimmune thyroid conditions where the immune system targets the thyroid gland.
Why it is done
It is used to find out whether an underactive or overactive thyroid is caused by autoimmune disease (such as Hashimoto’s thyroiditis or Graves’ disease), and to assess the risk of thyroid problems developing, including in pregnancy.
What to expect
It is an ordinary blood test from a vein in the arm, usually done together with thyroid function tests (TSH and thyroid hormones). No special preparation is needed.
Understanding the results
Raised thyroid antibodies suggest an autoimmune cause of thyroid dysfunction and a higher chance of ongoing thyroid problems. The result is interpreted alongside thyroid function tests and symptoms.
Good to know
Risks and limitations
It is a safe blood test. Some people have raised antibodies without current thyroid problems, so the result guides risk and cause rather than making a diagnosis alone.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
Thyroid Antibody Test: frequently asked questions
What does it mean if my thyroid antibodies are high?
Raised antibodies indicate an autoimmune process affecting the thyroid, which increases the likelihood of an underactive or overactive thyroid now or in the future. Your thyroid hormone levels show whether the gland is currently affected.
Do raised thyroid antibodies need treatment?
The antibodies themselves are not treated. Treatment depends on whether your thyroid is underactive or overactive, based on your thyroid function tests and symptoms.
Related tests
Other blood test investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- Association for Laboratory Medicine / relevant professional body
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