# Thyroid-stimulating Immunoglobulin (TSI)

> This test measures the level of thyroid-stimulating immunoglobulin (TSI), an antibody that mistakenly signals your thyroid gland to produce too much hormone. It helps doctors determine if an overactive thyroid is caused by the immune system, often investigating symptoms like rapid heartbeat or unexplained weight loss. This measurement is primarily used to help identify Graves' disease. However, the test result must be reviewed alongside other thyroid function tests and a physical exam to confirm a diagnosis.

- Labcorp code: 140749
- Category: [Thyroid](https://app.picardo.health/labs/tests/thyroid.md)
- Price: shown at checkout, before payment.
- Blood draw: free at a Labcorp location, or $75.00 at home.
- Order link: https://app.picardo.health/labs/order?tests=140749&ref=assistant

## About ordering

A licensed physician reviews every order before any test is run, and results arrive in the person's Picardo account. Ordering is open to adults 18 and over in the US, except New York, New Jersey, Rhode Island, Pennsylvania, Maryland, Massachusetts, Hawaii and Maine. General health information, not medical advice.