Protein C, Antigen

Overview

  • EPIC Code:
  • IMO203
  • Soft Test Code:
  • PCAG
  • Send Out Test Code:
  • 19673 / 4948X
Alternate Names
  • Antigen, Protein C
  • PC Antigen
  • Protein C
  • Protein C, Ag
Clinical Significance

Aids in characterization of congenital 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: vitamin K antagonists (eg. warfarin) will decrease PC antigen levels. PC antigen testing is not impacted by other anticoagulants (heparins, and target specific anticoagulants such as Dabigatran, Argatroban, Rivaroxaban, Apixaban, Edoxaban).


Specimen Collection & Preparation

Specimen Overview

If multiple special coagulation assays ordered, submit a separate, frozen vial for each one.

Specimen Requirements:

-OR-

1.0 mL Platelet Poor Plasma from a Blue Top Tube - 3.2% Na Citrate in a Plastic Vial
Minimum Volume:
0.5 mL Platelet Poor Plasma*

* This volume does not allow for repeat testing

Collection Instructions:

Draw blood in light blue-top tube containing 3.2% sodium citrate.

Mix gently by inverting 3-4 times.


Processing Instructions:

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


Rejection Criteria:

Gross hemolysis


Transport and Storage:
  • Ambient: Unacceptable
  • Refrigerated: Unacceptable
  • Frozen (-20 C or colder): 14 Days

    Preferred

    Transport on dry ice

  • Ultra Frozen (-70 C or colder or by dry ice): 1 Year

Clinical Interpretation

Reference Range:

0 - 15 years: No reference range available 

> or = 16 years: 70-140% of normal 


Methodology:
  • Enzyme Immunoassay (EIA)
Clinical Significance

Aids in characterization of congenital 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: vitamin K antagonists (eg. warfarin) will decrease PC antigen levels. PC antigen testing is not impacted by other anticoagulants (heparins, and target specific anticoagulants such as Dabigatran, Argatroban, Rivaroxaban, Apixaban, Edoxaban).


Production Schedule

Sites Performed
  • Quest - Chantilly
Days Performed
Monday
Tuesday
Wednesday
Thursday
Friday
Departments
  • Sendouts - Clinical
Turn Around Time

1 to 4 days


Coding & Compliance

CDM

00910614


CPT Coding

85302


Medical Necessity Documentation

Recommended as outpatient testing only