Protein S Antigen, Total and Free

Test Code

PRSTF

CPT Codes
85305, 85306

Preferred Specimen

2 mL platelet-poor plasma collected in a 3.2% sodium citrate (light blue-top) tube

Minimum Volume

1mL

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 screw-cap vial

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable Refrigerated: Unacceptable Frozen -20C: 30 days Frozen -70C: 1 year

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

Hemolysis

Methodology

Immunoturbidimetric

Setup Schedule

Set up: Tues-Sat p.m.; Report available: Next day

Limitations

Protein S Antigen, Total: 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.

Protein S Antigen, Free: Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: decrease; Heparin (UFH or LMWH): no effect; Dabigatran or Argatroban (Thrombin Inhibitors): no effect; Rivaroxaban or Apixaban (Factor Xa Inhibitors): no effect.

Reference Range

Protein S Antigen, Total	70-140 % normal
Protein S Antigen, Free
Male	57-171 % normal
Female	50-147 % normal

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

Last Updated: February 23, 2012

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.