Preferred Specimen(s) 1 mL platelet-poor plasma collected in a 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
Methodology Clotting Assay
Clinical Significance Aids in diagnosis of decreased activity of Protein C characterized by recurrent venous thrombosis. Acquired deficiencies associated with Protein C include: oral anticoagulant therapy, liver disease, vitamin K deficiency, malignancy, consumptive DIC, surgery, trauma, antibodies to Protein C and hepatic immaturity of the newborn.