Site Map

TSI test

TSH receptor stimulating antibody; Thyroid stimulating immunoglobulin; Hypothyroidism - TSI; Hyperthyroidism - TSI; Goiter - TSI; Thyroiditis - TSI

TSI stands for thyroid stimulating immunoglobulin. TSIs are antibodies that tell the thyroid gland to become more active and release excess amounts of thyroid hormone into the blood. A TSI test measures the amount of thyroid stimulating immunoglobulin in your blood.

Images

Blood test

How the Test is Performed

A blood sample is needed.

How to Prepare for the Test

No special preparation is usually necessary.

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

Your health care provider may recommend this test if you have signs or symptoms of an overactive thyroid (hyperthyroidism), including symptoms of:

The test is also done during the last 3 months of pregnancy to predict Graves disease in the baby.

The TSI test is most commonly done if you have signs or symptoms of hyperthyroidism but are unable to have a test called thyroid uptake and scan.

This test is not commonly done because it is expensive. Most of the time, another test called TSH receptor antibody test is ordered instead.

Normal Results

Normal values are less than 130% of basal activity.

Normal value ranges may vary slightly among different laboratories. Some laboratories use different measurements or may test different specimens. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

A higher-than-normal level may indicate:

Risks

There is little risk involved with having your blood taken.Veins and arteries vary in size from one person 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:

Related Information

Graves disease
TSH test

References

Chuang J, Gutmark-Little I. Thyroid disorders in the neonate. In: Martin RJ, Fanaroff AA, Walsh MC, eds. Fanaroff and Martin's Neonatal-Perinatal Medicine. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 88.

Cohen R, Kopp PA, Larsen PR. Thyroid pathophysiology and diagnostic evaluation. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 11.

Guber HA, Oprea M, Rusell YX. Evaluation of endocrine function. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 25.

Weiss RE, Refetoff S. Thyroid function testing. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 78.

BACK TO TOP

Review Date: 1/9/2022  

Reviewed By: Robert Hurd, MD, Professor of Endocrinology and Health Care Ethics, Xavier University, Cincinnati, OH. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

ADAM Quality Logo
Health Content Provider
06/01/2025

A.D.A.M., Inc. is accredited by URAC, for Health Content Provider (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics. This site complied with the HONcode standard for trustworthy health information from 1995 to 2022, after which HON (Health On the Net, a not-for-profit organization that promoted transparent and reliable health information online) was discontinued.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2024 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.