Protein C Activity with Reflex to Protein C Antigen (8754X)

Test Code

8754N

CPT Codes
85303

Includes

If Protein C Activity is <70%, then Protein C Antigen will be performed at an additional charge (CPT code(s): 85302).

Preferred Specimen

1 mL frozen platelet-poor plasma collected in each of two 3.2% sodium citrate (light blue-top) tubes

Minimum Volume

0.5 mL (x2)

Instructions

Please submit a separate, frozen vial for each special coagulation assay ordered. 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). Freeze immediately and transport on dry ice.

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 14 days

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

Gross hemolysis

Methodology
Clotting Assay

Setup Schedule

A.M. Sets up 6 days a week.

Report Available

Reports in 3 to 5 days.

Clinical Significance

Aids in characterization of protein C deficiency. Type I deficiency is characterized by reduction in activity (functional) and antigen levels. With type II deficiency (dysfunctional protein), antigen levels may be normal and activity levels are decreased. Acquired deficiencies may occur with vitamin K antagonists/deficiency, liver disease, malignancy, consumptive DIC, surgery, trauma, and hepatic immaturity of the newborn. Drug therapy with L-asparaginase or fluorouracil can also reduce Protein C antigen levels.

Anticoagulant interference: Expected impact by therapeutic levels (potential interference depends upon drug concentration): Vitamin K Antagonists (eg coumadin): 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.

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.