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Protein S, Total Antigen
Test Code5165
CPT Codes
85305
Preferred Specimen
1 mL frozen citrated plasma collected in a 3.2% sodium citrate (light blue-top) tube
Minimum Volume
0.5 mL
Instructions
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). Plasma must be free of platelets (<10,000/mcL). Freeze immediately and transport on dry ice.
Transport Container
Plastic vial
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 • Received room temperature • Received refrigerated • Received thawed
Methodology
Immunoturbidimetric
Setup Schedule
Set up: Tues-Sat; Report available: Next day
Limitations
Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: no effect to decrease; Heparin (UFH or LMWH): no effect; Dabigatran or Argatroban (Thrombin Inhibitors): no effect; Rivaroxaban or Apixaban (Factor Xa Inhibitors): no effect.
Reference Range
70-140 % normal
Clinical Significance
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).
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).
Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153