Protein S Activity

Test Code

CPT Codes

Preferred Specimen
1 mL frozen platelet-poor plasma collected in 3.2% sodium citrate (light blue-top) tube

Minimum Volume
0.5 mL

Centrifuge light blue-top tube for 15 minutes at approximately 1500 g within 60 minutes 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. Plasma must be free of platelets (<10,000/mcL). Freeze immediately and ship on dry ice.

Transport Container
Plastic vial

Transport Temperature

Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 30 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Clot Detection

Setup Schedule
Set up: Tues-Sat; Report available: 1-3 days

Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: decrease; Heparin (UFH or LMWH): may falsely increase at values approximately greater than 1.0 IU/mL; Dabigatran or Argatroban (Thrombin Inhibitors): may falsely increase; Rivaroxaban or Apixaban (Factor Xa Inhibitors): may falsely increase.

Reference Range
Male 70-150 % normal
Female 60-140 % 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: 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 (Direct Thrombin Inhibitors): may falsely
increase activity; Rivaroxaban, Apixaban, Edoxaban (Factor Xa Inhibitors): may falsely increase activity.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.