# Triiodothyronine (T3), Free

> This test measures the amount of free triiodothyronine (T3) in your blood, which is the active form of a thyroid hormone that is not attached to proteins. It helps show how well your thyroid is regulating your body's energy and metabolism, particularly if you have symptoms like rapid heartbeat or unexplained weight loss.

- Labcorp code: 010389
- Category: [Thyroid](https://picardo.health/labs/tests/thyroid.md)
- Sample: blood
- Labcorp turnaround: 1–2 days
- Collection: free at a Labcorp location, or $75.00 at home.
- Without a doctor: yes. People order it themselves, with no doctor's visit or referral.
- Price: shown on the review page its order link opens. Opening it orders nothing.
- Order link: https://app.picardo.health/labs/order?tests=010389&ref=assistant
- Already in these panels: [Postpartum Panel](https://picardo.health/labs/panels/postpartum.md), [Thyroid & Autoimmunity](https://picardo.health/labs/panels/thyroid-autoimmunity.md)

## About ordering

People order for themselves, with no doctor's visit or referral, and results arrive in their 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.