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.
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 temporarily stop taking medicines that may affect the test results.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed
This test helps detect possible thyroid problems. Antithyroglobulin antibodies can be a sign of thyroid gland damage caused by the immune system. Such antibodies are more likely to appear after thyroid gland swelling (inflammation) or injury.
Thyroglobulin antibody is also measured to monitor patients who have had their thyroid gland removed because 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.
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)
Guber HA, Farag AF. Evaluation of endocrine function. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 24.
Salvatore D, Davies TF, Schlumberger MJ, et al. Thyroid physiology and diagnostic evaluation of patients with thyroid disorders. In: Melmed S, Polonsky KS, Larsen PR, et al., eds. Williams Textbook of Endocrinology. 12th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 11.
Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.