Protein C Activity and Antigen

Last Modified: 7/29/2020 1:53:31 PM


Medical Necessity Documentation:  
Client Notes:  
Patient Preparation:  
Specimen Requirements: (2) 2.0 mL Plasma from a Blue Top Tubes - 3.2% Na Citrate in a Plastic Vials
Collection Instructions:
Draw blood in light blue-top tube containing 3.2% sodium citrate, and mix gently by inverting 3-4 times. 
Centrifuge 15 minutes at 1500 x 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(s). 
Freeze immediately and transport on dry ice.

Avoid Hemolysis 

Avoid presence of microclots
Minimum Volume: 0.5 mL Plasma (x2)
Transport & Storage: Temperature/Stability: 14 days Frozen (-20°)
1 year Frozen (-70°)
Rejection Criteria: Gross hemolysis
Reference Range:
Protein C Activity 70-180 % normal
Protein C Antigen 70-140 % normal
Critical Ranges:  
Test Comments:

Limitations

Protein C, Activity: Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: decrease; Heparin (UFH or LMWH): UFH-no effect, LMWH-may falsely increase at higher levels; Dabigatran or Argatroban (Thrombin Inhibitors): may falsely increase; Rivaroxaban or Apixaban (Factor Xa Inhibitors): may falsely increase.

Protein C, Antigen: 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.
Methodology: Clotting Assay • Immunoassay (IA)
Clinical Significance: Comprehensive test assesses the total level of protein and its functional activity in determining Protein C deficiency, which is strongly prothrombotic, and may require long-term anticoagulation therapy. In the presence of low Protein C Activity, Protein C Antigen helps to confirm and to classify Protein C Deficiency as Type I or Type II. Protein C is a highly thrombophilic protein
Documentation:  
Custom Panel: No

PRODUCTION SCHEDULE

Turn Around Time: 1 to 2 days
Days Performed: Monday, Tuesday, Wednesday, Thursday, Friday
Sites Performed: Quest - Chantilly
PHL Test Code: MSOT
EPIC Test Code:
Send Out Test Code: 141183
Alternate Test Names: Protein C Activity & Antigen
Included Tests: Protein C Antigen; Protein C, Activity
CPT Coding: 85302, 85303

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