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Protein S Activity, Antigen, Total and Free
Test Code93355
CPT Codes
85305, 85306 (x2)
Includes
Protein S Antigen, Total
Protein S Antigen, Free
Protein S Activity
Protein S Antigen, Free
Protein S Activity
Preferred Specimen
1 mL frozen platelet-poor plasma (x2) collected in separate 3.2% sodium citrate (light blue-top) tubes
Minimum Volume
0.5 mL (x2)
Instructions
Please submit a separate, frozen vial for each special coagulation assay ordered. Draw blood in a light blue-top tube containing 3.2% sodium citrate, mix gently by inverting 3-4 times. Centrifuge 15 minutes at 1500 g within one hour of collection. 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(s). Freeze immediately and transport on dry ice.
Transport Container
Plastic vials
Transport Temperature
Frozen
Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 30 days
Refrigerated: Unacceptable
Frozen: 30 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolysis
Methodology
Clotting Assay • Immunoturbidimetric Assay
Setup Schedule
Set up and Report available: See individual assays
Reference Range
See individual tests
Clinical Significance
Protein S deficiency may either be hereditary or acquired and is associated with an increased risk for
venous thromboembolic disease. Congenital Protein S (PS) deficiency may be classified based on the PS Antigen (Free and Total) and activity results. Type I deficiency is characterized by a decrease in antigen and activity levels whereas a Type II deficiency will have normal antigen levels but reduced activity. A third classification, Type III deficiency, is characterized by reduced free PS antigen and activity, but normal total PS antigen levels associated with increased C4b binding protein level.
Anticoagulant interference: Expected impact by therapeutic levels (potential interference depends upon drug concentration): Vitamin K Antagonists (eg. warfarin): decrease; Heparin (UFH or LMWH): no effect to falsely increased activity levels at higher levels; Dabigatran or Argatroban (Thrombin Inhibitors): may falsely increase activity; Rivaroxaban, Apixaban, Edoxaban (Factor Xa Inhibitors): may falsely increase activity.
venous thromboembolic disease. Congenital Protein S (PS) deficiency may be classified based on the PS Antigen (Free and Total) and activity results. Type I deficiency is characterized by a decrease in antigen and activity levels whereas a Type II deficiency will have normal antigen levels but reduced activity. A third classification, Type III deficiency, is characterized by reduced free PS antigen and activity, but normal total PS antigen levels associated with increased C4b binding protein level.
Anticoagulant interference: Expected impact by therapeutic levels (potential interference depends upon drug concentration): Vitamin K Antagonists (eg. warfarin): decrease; Heparin (UFH or LMWH): no effect to falsely increased activity levels at higher levels; Dabigatran or Argatroban (Thrombin Inhibitors): may falsely increase activity; Rivaroxaban, Apixaban, Edoxaban (Factor Xa Inhibitors): may falsely increase activity.
