Protein S Antigen, Free
Test Code
Clinical Significance
Protein S Antigen, Free - Protein S (PS) deficiency may be congenital or acquired and is associated with venous thrombosis. Acquired PS deficiency may occur with vitamin K antagonists/deficiency, liver disease, malignancy, consumptive DIC, surgery, trauma, and hepatic immaturity of the newborn. In addition, PS
deficiency is physiologic in pregnancy.
Anticoagulant interference: Vitamin K Antagonists (eg. warfarin) will decrease PS antigen levels. PS antigen testing is not impacted by other anticoagulants (heparins, and target specific anticoagulants such as Dabigatran, Argatroban, Rivaroxaban, Apixaban, Edoxaban).
Test Resources
Please visit our Clinical Education Center to stay informed on any future publications, webinars, or other education opportunities.
Test Details
Methodology
Reference Range(s)
| Male | 57-171 % normal |
| Female | 50-147 % normal |
Preferred Specimen(s)
1 mL frozen plasma collected in a 3.2% sodium citrated (light blue-top) tube
Minimum Volume
0.5 mL
Collection 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 g within 1 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. Freeze immediately and ship on dry ice.
Transport Container
Transport tube
Transport Temperature
Frozen
Specimen Stability
- Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 30 days
Setup Schedule
Refrigerated: Unacceptable
Frozen: 30 days