# Triiodothyronine (T3)

> This test measures the level of triiodothyronine (T3), a hormone produced by your thyroid gland that helps control how your body uses energy. It helps show whether your thyroid is overactive, particularly in cases where other thyroid tests appear normal despite symptoms like unexplained weight loss or a rapid heartbeat. This measurement assists in evaluating specific forms of hyperthyroidism. However, this test is generally not used to diagnose an underactive thyroid because levels often remain normal even when function is low.

- Labcorp code: 002188
- 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=002188&ref=assistant
- Already in these panels: [Thyroid & Autoimmunity](https://app.picardo.health/labs/panels/thyroid-autoimmunity.md)

## 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.