Protein S Activity, Antigen, Total and Free
Test Code
Clinical Significance
Protein S Activity, Antigen, Total and Free - 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 ...
Test Resources
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Test Details
Protein S Antigen, Free
Protein S Activity
Methodology
Reference Range(s)
Alternative Name(s)
Preferred Specimen(s)
1 mL plasma collected in each of two 3.2 % separate sodium citrate (light blue-top) tubes
Minimum Volume
0.5 mL per specimen
Collection 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
Transport tube(s)
Transport Temperature
Frozen
Specimen Stability
- Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 30 days
Reject Criteria
Hemolysis
Setup Schedule
Refrigerated: Unacceptable
Frozen: 30 days