Preferred Specimen(s) 1 mL platelet poor plasma 3.2% sodium citrate in (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
- Hemolysis
- Received thawed
Methodology Clot Detection
Clinical Significance The congenital or acquired deficiency of Protein S increases the risk for thromboembolism, owing to a decrease of blood anticoagulant potential. It results in recurring thrombotic episodes. A decrease of Protein S leads to a greater risk of thromboembolism.