Also known as: Protein C Activity; Protein C Level; Protein S Activity; Protein S Level
Formal name: Protein C, Functional or Antigen; Protein S, Functional or Antigen (Free or Total)
At a Glance
Why Get Tested?
To help evaluate inappropriate blood clot formation ( or thromboembolism); to determine whether you may have a protein C or protein S deficiency
When to Get Tested?
When you have had an unexplained blood clot; when your newborn has a severe clotting disorder; sometimes when a close relative has an inherited protein C or protein S deficiency
A blood sample drawn from a vein in your arm
Test Preparation Needed?
You must wait at least 10 days after a thrombotic episode and be off oral warfarin (Coumadin®) therapy for 2 weeks before having this test done. (See also Common Questions #1.)