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| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Protein C Activity
Message
SRHC Clients:
Outpatients: Send patient to SRHC laboratory for collection due to processing and stability requirements
Inpatients:
- 1 light blue top tube (3.2% Sodium Citrate)
- FULL TUBE REQUIRED. Correct blood to anticoagulant ratio is crucial for accurate results.
- Transport to SRHC laboratory immediately for processing
- Must be centrifuged for platelet-poor plasma and frozen at -70C within 1 hour of collection
- Patient must be off Coumadin for 2 weeks and Heparin for 2 days prior to collection
Test Code
LAB489
Quest Code
1777
CPT Codes
85303
Preferred Specimen
1 mL platelet -poor citrated plasma (0.5 mL minimum)
Minimum Volume
0.5 mL (if single test)
Instructions
Preparation of Platelet Poor Plasma
- Centrifuge light blue-top tube 15 minutes at 3000 rpm 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. Plasma must be free of platelets (< 10,000/mcl).
- Freeze immediatelyand ship on dry ice.
Transport Container
Plastic vial
Transport Temperature
Frozen, at -70C
Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 14 days
Refrigerated: Unacceptable
Frozen: 14 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Samples received at Quest thawed
Hemolyzed specimens are not acceptable
3.8% Sodium Citrate is not acceptable
Methodology
Clotting Assay
Setup Schedule
Set up: Tues-Sat; Report available: 1-4 days
Limitations
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.
Reference Range
| 0-15 years | No reference range available |
| ≥16 years | 70-180 % normal |
Clinical Significance
Protein C (PC) deficiency may be congenital or acquired and is associated with venous thrombosis. Acquired PC deficiency may occur with vitamin K antagonists/deficiency, liver disease, malignancy, consumptive DIC, surgery, trauma, and hepatic immaturity of the newborn.
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 (Thrombin Inhibitors): may falsely increase activity; Rivaroxaban, Apixaban, Edoxaban (Factor Xa Inhibitors): may falsely increase activity.
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 (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
