Antithyroglobulin antibody is a test to measure antibodies to a protein called thyroglobulin, which is found in thyroid cells.
How the test is performed
A blood sample is needed. For information on how this is done, see: Venipuncture
How to prepare for the test
You may be told not to eat or drink anything for several hours before the test (usually overnight). Your doctor may monitor you or tell you to stop taking medications that may affect the test results until after the test.
How the test will feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the test is performed
This test helps detect possible thyroid problems. Antithyroglobulin antibodies can lead to the destruction of the thyroid gland. Such antibodies are more likely to appear after thyroid gland swelling (inflammation) or injury.
Thyroglobulin antibody is also measured. Sometimes the thyroglobulin level is measured too, for example to follow up on some types of thyroid cancer.
A negative test is normal -- it means no antibodies to thyroglobulin are found in your blood.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What abnormal results mean
A positive test means antithyroglobulin antibodies are found in your blood. This may be due to:
Pregnant women and relatives of those with autoimmune thyroiditis may also test positive for these antibodies.
What the risks are
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
Fainting or feeling light-headed
Hematoma (blood accumulating under the skin)
Infection (a slight risk any time the skin is broken)
Ladenson P, Kim M. Thyroid. In: Goldman L and Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders; 2007:chap 244.
Shehzad Topiwala, MD, Chief Consultant Endocrinologist, Premier Medical Associates, The Villages, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.