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Thyroid Blood Tests


Updated May 29, 2014

Thyroid Blood Tests
TSI monitoring is especially important during pregnancy, because elevated levels, particularly in early pregnancy and during the third trimester, are a risk factor for fetal or neonatal thyroid dysfunction. The mother's TSI antibodies can transfer to the unborn baby via the placenta, making a baby hyperthyroid in utero, or at birth. Research has shown that as many as 10 percent of pregnant women with elevated TSI deliver hyperthyroid babies.

Blocking Thyroid Receptor Antibodies

Blocking TSH receptor antibodies, sometimes abbreviated TBAb or TSBAb, are antibodies that prevent TSH from binding to the cell receptor, and cause hypothyroidism. Patients with Hashimoto's disease tend to test positive for these antibodies.


Braverman, MD, Lewis E., and Robert D. Utiger, MD. Werner and Ingbar's The Thyroid: A Fundamental and Clinical Text. 9th ed., Philadelphia: Lippincott Williams & Wilkins (LWW), 2005.

Roti, Elio, et. al. "TSH Receptor Antibody Measurement in the Diagnosis and Management of Graves' Disease Is Rarely Necessary," The Journal of Clinical Endocrinology & Metabolism, Vol. 83, No. 11 3781-3784 http://jcem.endojournals.org/cgi/content/full/83/11/3781

Spencer, Carol. "Assay of Thyroid Hormones and Related Substances," Thyroid Manager. February 6, 2004. http://www.thyroidmanager.org/Chapter6/Ch-6-6.htm

Mary Shomon, About.com's Thyroid Guide since 1997, is a nationally-known patient advocate and best-selling author of 10 books on health, including "The Thyroid Hormone Breakthrough: Overcoming Sexual and Hormonal Problems at Every Age," "The Thyroid Diet: Manage Your Metabolism for Lasting Weight Loss," "Living Well With Hypothyroidism: What Your Doctor Doesn't Tell You...That You Need to Know," "Living Well With Graves' Disease and Hyperthyroidism," "Living Well With Autoimmune Disease," and "Living Well With Chronic Fatigue Syndrome and Fibromyalgia." Click here for more information on Mary Shomon.

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