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Protein C, Activity
1 mL platelet-poor plasma (LB, light blue-top tube, 3.2%
sodium citrate), frozen -20 degrees C or frozen -70
Minimum: 0.5 mL (if a single test)
Refrigerated (cold packs): Unacceptable
Frozen -20 degrees C: 14 days
Frozen -70 degrees C: 1 year
Please submit a separate, frozen vial for each special
coagulation assay ordered.
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
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153
Report available: Next Day
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.
70-180% of normal
Aids in diagnosis of decreased activity of Protein C characterized by recurrent venous thrombosis. Acquired deficiencies associated with Protein C include: oral anticoagulant therapy, liver disease, vitamin K deficiency, malignancy, consumptive DIC, surgery, trauma, antibodies to Protein C and hepatic immaturity of the newborn.
Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.
(The CPT codes provided 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 payer being billed.)
* The tests listed by specialist are a select group of tests offered. For a complete list of Quest Diagnostics tests, please refer to our Directory of Services.