# Protein S Antigen

> This test measures the amount of Protein S in your blood, a substance that helps prevent dangerous blood clots from forming. It is useful for determining if a shortage of this protein is causing unexplained clots or contributing to a family history of clotting disorders. While this test helps identify a specific deficiency, it cannot diagnose other causes of blood clots or determine the exact reason for the low levels without further evaluation.

- Labcorp code: 164517
- Category: [Heart & Metabolic](https://app.picardo.health/labs/tests/heart-metabolic.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=164517&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.