Thyroid Antibodies Test
This test checks for thyroid antibodies in your blood. If found, they may mean an autoimmune disease like Hashimoto's or Graves' is affecting your thyroid.
What this test measures
A thyroid antibody test measures the level of thyroid antibodies in a sample of your blood. Antibodies are proteins your immune system makes, but sometimes they attack your thyroid by mistake, causing autoimmune disease.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
Positive results for thyroid antibodies (TPOAb, TgAb, or TRAb) may mean you have Hashimoto's disease or Graves' disease, depending on which antibodies are found.
Frequently asked questions
What are thyroid antibodies?
They are proteins your immune system makes that can attack your thyroid by mistake, causing autoimmune disease.
What does a positive test result mean?
It means thyroid antibodies were found. Depending on the type, it may indicate Hashimoto's disease or Graves' disease.
What does a negative test result mean?
It means no thyroid antibodies were found, so your thyroid symptoms are probably not caused by an autoimmune disease.
What is Hashimoto's disease?
It is an autoimmune disease that causes hypothyroidism (underactive thyroid). Most people with it have high levels of TPOAb or TgAb.
What is Graves' disease?
It is an autoimmune disease that causes hyperthyroidism (overactive thyroid). It is linked to TRAb antibodies.
Related lab tests
Sources
- MedlinePlus: Thyroid Antibodies — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.