Thyroid-Stimulating Immunoglobulin
Also written as: TSI — Thyroid-Stimulating Immunoglobulin
Antibodies that mimic TSH action by binding to TSH receptors, causing hyperthyroidism in Graves' disease.
Full Definition
Thyroid-stimulating immunoglobulin (TSI) refers to antibodies that bind to and activate the thyroid-stimulating hormone receptor, mimicking the action of TSH. These antibodies are the primary cause of Graves' disease, leading to excessive thyroid hormone production and thyroid gland enlargement. TSI measurement is crucial for diagnosing Graves' disease, predicting relapse after antithyroid drug therapy, and assessing the risk of neonatal thyrotoxicosis in pregnant women with Graves' disease. Unlike TSH receptor antibodies (TRAb), TSI specifically measures stimulating activity.
Usage
Usage note: Hyphenate 'thyroid-stimulating' when used as compound adjective.
In Context
- "Elevated thyroid-stimulating immunoglobulin levels confirmed the diagnosis of Graves' disease." — Laboratory report
- "Persistent TSI positivity suggests continued risk of hyperthyroid relapse." — Endocrinology consultation