Thyroid Stimulating Immunoglobulin
TSI
Description
"Thyroid Stimulating Immunoglobulin" (TSI) test detects antibodies that cause the thyroid to overproduce hormones, often linked to Graves’ disease. Doctors may order this test when symptoms such as rapid heartbeat, weight loss, or a swollen neck are present. Elevated TSI levels point to autoimmune hyperthyroidism. This test helps confirm diagnosis and guide treatment decisions like medications, lifestyle changes, or additional evaluation. Ongoing testing helps manage hormone fluctuations and reduces the risk of complications over time.
Category
Autoantibodies, Proteins
Procedure
Invasive
Sample Type
Blood – Serum
Units
International Units Per Liter | Percentage of Basal Activity
Procedure Category
Blood Draw
Test Group
Complete Thyroid Group, Autoimmune Condition Group
Test Group Description
Complete Thyroid Group: A comprehensive array of tests for a thorough evaluation of thyroid function, providing detailed insights into thyroid health and associated conditions. Autoimmune Condition Group: Tests within this group focus on markers associated with autoimmune diseases, providing insights into the body's immune response against its own tissues.
Optimal Range
For All Individuals:
Conventional Unit: < 1.0 TSI Index | < 0.10 IU/L | ≤ 100% Basal Activity
SI Unit: Not Applicable
Normal Range
For All Individuals:
Conventional Unit: ≤ 1.3 TSI Index | ≤ 0.54 IU/L | ≤ 130% Basal Activity
SI Unit: Not Applicable
Results That Differ From The Norm (Direct and Indirect Causes)
Increased levels may indicate:
Graves' disease (Autoimmune hyperthyroidism)
Hashitoxicosis (Transient hyperthyroidism in Hashimoto's thyroiditis)
Neonatal Graves' disease (Transient hyperthyroidism in newborns)
Toxic nodular goiter (Enlarged thyroid with overactive nodules)
Postpartum thyroiditis (Thyroid inflammation after childbirth)
Key Reasons For Testing
Graves' Disease Diagnosis: TSI is essential for confirming Graves’ disease, the most common autoimmune hyperthyroidism.
Differentiation of Thyroid Disorders: TSI distinguishes Graves’ from Hashimoto’s or toxic multinodular goiter, ensuring accurate treatment.
Monitoring Response to Treatment: TSI levels track therapy effectiveness in managing Graves’ disease.
Predictive Marker for Graves' Ophthalmopathy: TSI indicates risk and severity of this serious complication, guiding early intervention.
Health Status Conditions It May Be Used To Assess
Currently, this test is not directly associated with any conditions listed on the Health Status page. However, it may be included as part of a broader set of tests linked to specific health conditions.
Some Prominent Medical Labs That May Offer This Test
Please note that this particular test has not been associated with any of the listed prominent medical labs. We recommend enquiring with your private physician or nearest hospital to determine where this specific test can be performed.
References
Important Note
Any medical procedure yielding results outside the norm may be directly or indirectly linked to the conditions outlined on this page. Various factors, including genetics, medication and supplement usage, recent illnesses, pregnancy, pre-test eating, smoking, and stress, can impact the test's outcome. Additionally, factors like false positives, false negatives, inaccurate analyses, and others can influence results.
Reference ranges, which help healthcare professionals interpret medical tests, may vary depending on age, gender, and other factors. They may also differ between laboratories due to variations in instruments and methods used. Optimal ranges are designed for preventive purposes, aiming to identify trends and potential risks early, while normal ranges reflect conventional laboratory values indicating no current disease or pathology. Your healthcare practitioner may have specific reasons for testing that deviate from the usual or may interpret results differently based on individual circumstances. Proper interpretation typically involves considering clinical findings and other diagnostic tests. Hence, it is crucial to provide your healthcare professionals with a comprehensive medical history, consult with them for result interpretation, and follow their guidance for potential re-testing or additional diagnostics.
Disclaimer
This content is provided solely for informative and educational purposes. It is not intended as a substitute for medical advice or treatment from a personal physician. Regarding the interpretation of their medical test results and/or specific health questions, it is recommended that all readers and viewers consult their physicians or other qualified health professionals. The publisher is not responsible for any adverse health effects that may result from reading or following the information in this educational content. Before beginning any nutrition, supplement, or lifestyle program, all viewers, especially those taking prescription or over-the-counter medications, should consult their physician or health care practitioner.
Please note that while prominent lab names are included in this content, we cannot guarantee that these labs offer all the tests mentioned. For confirmation, individuals should contact the labs directly or consult their medical practitioners. The information provided reflects general knowledge at the time of publication and may not include recent updates or emerging research. Readers should verify details with qualified professionals to ensure the most up-to-date and accurate guidance.
[1] McIver B, Morris JC. The pathogenesis of Graves' disease. Endocrinol Metab Clin North Am. 1998;27(1):73-89.
[2] Bahn RS. Graves' ophthalmopathy. N Engl J Med. 2010;362(8):726-738.
[3] Smith TJ, Hegedüs L. Graves' disease. N Engl J Med. 2016;375(16):1552-1565.
[4] Ross DS, Burch HB, Cooper DS, et al. 2016 American Thyroid Association guidelines for diagnosis and management of hyperthyroidism and other causes of thyrotoxicosis. Thyroid. 2016;26(10):1343-1421.
[5] Kahaly GJ, Diana T, Glang J, et al. Thyroid stimulating antibodies are highly prevalent in Hashimoto's thyroiditis and associated orbitopathy. J Clin Endocrinol Metab. 2016;101(5):1998-2004.
[6] Tozzoli R, Bizzaro N, Tonutti E, et al. Immunoassay of anti-thyroid autoantibodies: high analytical variability in second generation methods. Clin Chem Lab Med. 2002;40(6):568-573.
[7] Diana T, Wüster C, Kanitz M, Kahaly GJ. Highly variable sensitivity of five binding and two bio-assays of TSH-receptor antibodies. J Endocrinol Invest. 2016;39(10):1159-1165.
[8] Kamijo K. TSH receptor antibodies in Graves' disease: functional activities and clinical applications. Endocr J. 2000;47(4):471-482.
[9] Morshed SA, Latif R, Davies TF. Delineating the autoimmune mechanisms in Graves' disease. Immunol Res. 2012;54(1-3):191-203.
[10] Menconi F, Marcocci C, Marinò M. Diagnosis and classification of Graves' disease. Autoimmun Rev. 2014;13(4-5):398-402.
[11] Brent GA. Clinical practice. Graves' disease. N Engl J Med. 2008;358(24):2594-2605.
[12] Laurberg P, Wallin G, Tallstedt L, et al. TSH-receptor autoimmunity in Graves' disease after therapy with anti-thyroid drugs, surgery, or radioiodine: a 5-year prospective randomized study. Eur J Endocrinol. 2008;158(1):69-75.
[13] Wiersinga WM. Clinical relevance of TSH receptor autoantibodies. J Endocrinol Invest. 1995;18(5):381-383.
[14] Bartalena L, Tanda ML. Clinical practice. Graves' ophthalmopathy. N Engl J Med. 2009;360(10):994-1001.
[15] Burch HB, Cooper DS. Management of Graves disease: a review. JAMA. 2015;314(23):2544-2554.