# Protein S, Functional

> This test measures the activity of Protein S, a substance in your blood that helps stop clots from growing too large. It helps doctors investigate the cause of unexplained blood clots or a family history of clotting disorders. The results help show whether a deficiency in this protein is contributing to an increased risk for dangerous clots in your veins. However, this test does not diagnose the specific genetic cause of a deficiency on its own, and results can be affected by certain medications or other blood conditions.

- Labcorp code: 164525
- 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=164525&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.