LabCorp Test

Thyroid-stimulating Immunoglobulin (TSI) Blood Test

Quick Overview

Aids in the diagnosis of autoimmune disorders which affect the Thyroid.

Test #140749


Availability: In stock

Also Known As Human Thyroid Stimulator (HTS); Long-acting Thyroid Stimulator (LATS); Thyretain™; Thyroid-stimulating Antibody (TSAb); TSI; Thyroid Receptor Antibody
Preparation No special preparation required.
Test Results 6-7 days. May take longer based on weather, holiday or lab delays.

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

Second-order testing for autoimmune thyroid disease, including:

-Differential diagnosis of etiology of thyrotoxicosis in patients with ambiguous clinical signs and/or contraindicated (eg, pregnant or breast-feeding) or indeterminate thyroid radioisotope scans

-Diagnosis of clinically suspected Graves disease (eg, extrathyroidal manifestations of Graves disease: endocrine exophthalmos, pretibial myxedema, thyroid acropachy) but normal thyroid function tests

-Determining the risk of neonatal thyrotoxicosis in a fetus of a pregnant female with active or past Graves disease

-Differential diagnosis of gestational thyrotoxicosis versus first trimester manifestation or recurrence of Graves disease

-Assessing the risk of Graves disease relapse after anti-thyroid drug treatment

The laboratory tests most helpful for the diagnosis and monitoring of patients with Graves’ disease include the Free T4 (FT4), Free T3 (FT3), TSH test, and TSI test.

Thyroid-stimulating immunoglobulins (TSI) can be detected in the majority of patients (77.8%) with Graves' disease. These antibodies have also been associated with a small portion (15.9%) of patients with toxic multinodular goiter.  It has also been reported that TSI measurement can be used to predict relapse or remission when methimazole or radioiodine is used to treat Graves' disease. These assays have also been advocated for use in patients with subclinical Graves' hyperthyroidism or patients with unilateral ophthalmopathy.

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