Protein C Activity and Antigen

Preferred Specimen(s) 1 mL plasma in two separate tubes collected in a 3.2% Sodium Citrate (light blue-top) tube Instructions Draw blood in (light blue-top) tube containing 3.2% sodium citrate, mix gently by inverting 3-4 times. Centrifuge 15 minutes at 1500 RCF (relative centrifugal force). Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial. Freeze immediately and transport on dry ice.

Transport Container Plastic screw-cap vial

Transport Temperature Frozen

Reject Criteria

  • Received thawed
  • Hemolyzed samples
  • Received room temperature
  • Received refrigerated

Methodology Chromogenic Substrate; Enzyme immunoassay

Clinical Significance Comprehensive test assesses the total level of protein and its functional activity in determining Protein C deficiency, which is strongly prothrombotic, and may require long-term anticoagulation therapy. In the presence of low Protein C Activity, Protein C Antigen helps to confirm and to classify Protein C Deficiency as Type I or Type II. Protein C is a highly thrombophilic protein.