• Home

Home > Medical Reference > Encyclopedia (English)

Toggle: English / Spanish

TSI

• Overview
• Risks
• Results

Definition:

TSI is a test that measures the amount of TSI antibody in the blood.

Alternative Names:

TSH receptor antibody; Thyroid stimulating immunoglobulin

How the test is performed:

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to fill with blood. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. The tourniquet is then removed to restore circulation. After blood has been collected the needle is removed, and the puncture site is covered to stop any bleeding.

Infant or young child:

The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. A bandage may be applied to the puncture site if there is any bleeding.

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, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed:

This test may be performed as part of the diagnostic work-up of Graves' disease , Hashimoto's Thyroiditis , or toxic multinodular goiter . TSI measurements are also performed in the third trimester of pregnancy to predict neonatal Graves' disease.

TSI is an antibody directed against the receptor for TSH on the thyroid gland. This antibody interacts with the receptor and mimics the action of the pituitary hormone TSH. Thus TSI stimulates the gland to secrete excessive amounts of thyroid hormone.

• Review Date: 3/3/2006
• Reviewed By: David Juan, MD, Specializing in Endocrinology Issues, Good Hand Medical Center and Alperin Medical Clinics, Santa Clara, CA. Review provided by VeriMed Healthcare Network.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. 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 process . A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 1997-2007 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.