Thyroid-stimulating Immunoglobulin (TSI) Blood Test

The Thyroid-Stimulating Immunoglobulin (TSI) Blood Test measures TSI levels to help screen for Graves Disease and other thyroid-related disorders.

Quest
LabCorp

Test Code: 140749

CPT Code: 84445

Also Known As: TSI; Hyperthyroidism - TSI; Hypothyroidism - TSI; Goiter - TSI; Thyroiditis - TSI; Thyroid-Stimulating Antibody (TSAb)

Methodology:

Immulite 2000 TSI Assay

Specimen Type: Blood

Preparation:

No special preparation is required.

Test Results:

6-7 days. May take longer based on weather, holiday or lab delays.

Sample Report

Test Code: 30551

CPT Code: 84445

Also Known As: TSI; Hyperthyroidism - TSI; Hypothyroidism - TSI; Goiter - TSI; Thyroiditis - TSI; Thyroid-Stimulating Antibody (TSAb)

Methodology:

In Vitro Bioassay

Specimen Type: Blood

Preparation:

No special preparation is required.

Test Results:

6-7 days. May take longer based on weather, holiday or lab delays.

Description

What is the purpose of this test?

Order this Thyroid-Stimulating Immunoglobulin (TSI) Blood Test to measure TSI levels in the blood to help screen for Graves Disease and other thyroid-related autoimmune disorders. TSI are antibodies the immune system produces that can make the thyroid gland more active, resulting in an excessive amount of thyroid hormones in the blood.

The thyroid gland, located at the base of the neck, produces many thyroid hormones to help the body regulate metabolism, among many other functions. Unfortunately, many health conditions can affect the gland, leading to an over (hyperthyroidism) or underproduction (hypothyroidism) of thyroid hormones. Therefore, this test is typically ordered to help diagnose Graves Disease, screen pregnant women with a history of thyroid issues for neonatal thyrotoxicosis, and to aid in diagnosing other thyroid-related disorders such as Hashimoto's thyroiditis and toxic multinodular goiter.

What conditions are associated with abnormal TSI levels?

Thyroid disorders can range from a small, harmless goiter (enlarged gland) that needs no treatment to life-threatening cancer. Many thyroid disorders include:

Hypothyroidism
Hyperthyroidism
Graves Disease
Goiter
Neonatal thyrotoxicosis
Nodules
Thyroid cancer

High TSI levels may indicate that an individual has Graves disease. Hyperthyroidism is a thyroid disorder with the most noticeable symptoms and is commonly caused by Graves disease. Graves disease triggers the immune system to mistakenly attack itself by producing specific antibodies. As a result, these antibodies, similar to thyroid-stimulating hormones (TSH), cause the thyroid gland to produce hormones, more than is needed.

When should I order a TSI Blood Test?

Individuals may order this TSI Blood Test if they have experienced symptoms associated with hyperthyroidism. Hyperthyroidism symptoms may include: