TSH receptor stimulating antibody; Thyroid stimulating immunoglobulin; Hypothyroidism - TSI; Hyperthyroidism - TSI; Goiter - TSI; Thyroiditis - TSI DefinitionTSI 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. How the Test is PerformedA blood sample is needed. How to Prepare for the TestNo special preparation is usually necessary. How the Test will FeelWhen 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 PerformedYour 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 ResultsNormal 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 MeanA higher-than-normal level may indicate:
RisksThere 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:
ReferencesGuber HA, Oprea M, Russell 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. Hollenberg A, Wiersinga WM. Hyperthyroid disorders. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 12. Pearce EN, Hollenberg AN. Thyroid. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 207. Smith JR, Wassner AJ. Thyrotoxicosis. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 606. Weetman AP, Kahaly GJ. Graves disease. In: Robertson RP, ed. DeGroot's Endocrinology. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 71. | |
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Review Date: 2/28/2024 Reviewed By: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. 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. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. | |
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Blood test
