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Thyroid antibody tests measure the levels of antibodies that can destroy thyroid tissue or make the cells produce thyroid hormones. They are blood tests.
Antibodies that destroy thyroid tissue can lead to hypothyroidism (underactive thyroid). Antibodies that make the cells produce thyroid hormone can lead to hyperthyroidism (overactive thyroid).
The body's immune system makes antibodies to fight infections. But sometime those antibodies attack the body's tissues instead. This is called an autoimmune reaction.
People who have one autoimmune disease may get another one. Tell your doctor if you have any new or worse symptoms.
These tests are not thyroid hormone tests. High or low levels of thyroid hormones also can be signs of thyroid problems. These antibody tests may be done after thyroid hormone tests to find the cause of high or low levels of thyroid hormones.
High levels of these antibodies usually suggest that a person has an autoimmune thyroid problem. But some people who have thyroid problems don't test positive for these antibodies. And some people who have these antibodies don't get thyroid disease.
Thyroid antibody tests are usually done if you have a goiter or symptoms of thyroid disease.
The following tests may be done:
You do not need to do anything special to prepare for this test.
The health professional taking a sample of your blood will:
The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.
There is very little chance of a problem from having a blood sample taken from a vein.
Thyroid antibody tests look for and measure the levels of antibodies that can destroy thyroid tissue. They also can be used to find and measure antibodies that make thyroid cells produce thyroid hormone.
These numbers are just a guide. The range for "normal" for these tests can vary widely from lab to lab. Your lab may have a different range. Your lab report should show what range your lab uses for "normal." Also, your doctor will evaluate your results based on your health and other factors. So a number that is outside the normal range here may still be normal for you.
Thyroglobulin and thyroid microsomal antibodies:
Less than 1:100. (This test is measured in titers.)
Less than 9 IU/mL
Negative results for the tests mean that you don't have thyroid antibodies. If you have symptoms of thyroid problems, they are likely caused by something else.
High levels of these antibodies can show that there is a problem with your thyroid. You may have other tests to find out what is wrong.
If you have thyroid cancer and you have anti-thyroglobulin antibodies, your doctor may not be able to get accurate test results for your thyroglobulin levels.
Your doctor will use the results of a physical exam, your symptoms, and the results of these tests to find out if you have a thyroid disease.
Fischbach F, Dunning MB III (2015). A Manual of Laboratory and Diagnostic Tests, 9th ed. Philadelphia: Wolters Kluwer Health.
Pagana KD, Pagana TJ (2014). Mosby's Manual of Diagnostic and Laboratory Tests, 5th ed. St. Louis: Mosby.
Current as of: November 6, 2018
Author: Healthwise StaffMedical Review: E. Gregory Thompson, MD - Internal MedicineKathleen Romito, MD - Family MedicineMatthew I. Kim, MD - Endocrinology, Diabetes and Metabolism
Current as of:
November 6, 2018
Medical Review:E. Gregory Thompson, MD - Internal Medicine & Kathleen Romito, MD - Family Medicine & Matthew I. Kim, MD - Endocrinology, Diabetes and Metabolism
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