Thyroid Antibodies Test
Reviewed
This test measures the level of thyroid antibodies in your blood to help find out if an autoimmune disease is causing your thyroid to be underactive (hypothyroidism) or overactive (hyperthyroidism). Antibodies are proteins your immune system makes to fight foreign substances, but sometimes they mistakenly attack your own thyroid cells. High levels of certain antibodies can indicate Hashimoto's disease or Graves' disease.
Preparation and collection
No special preparations are needed.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- The test is not diagnostic on its own; results must be interpreted alongside thyroid hormone levels (T3, T4, TSH), your medical history, family history, and physical exam.
- Some people with autoimmune thyroid disease may have negative antibody tests, and some people without symptoms may have positive antibodies.
- Pregnancy can affect thyroid antibody levels and thyroid function, so results should be interpreted with caution during pregnancy.
What to do next
If you are diagnosed with Hashimoto's disease or Graves' disease, there are medicines you can take to manage your condition. Discuss all results and follow-up plans with your healthcare provider.