Protein C, Functional
Label Mnemonic: PCFX
Epic code: LAB1133
Order form: Laboratory Requisition
Supply order: Supply Order Form
Billing: Billing Policies
CPT code: 85303
Specimen(s):
Collection Medium:
Light Blue top tube 2.7 mL (Na Citrate)
Minimum:
Full draw; 2.7 mL light blue top
Rejection Criteria:
Short drawn tube, clot, traumatic tap (excessive hemolysis).
Testing Schedule:
0800-1630 Monday, Wednesday and Friday. If you need results STAT, call Hematology resident (0800-1630, M-F) at 356-8628. All other times page the Pathology resident on-call at 3404.
Turn Around Time:
1-3 days upon receipt in laboratory
Reference Range:
>=83%
Interpretive Data:
Patients on warfarin may have decreased protein C levels. Warfarin therapy should be discontinued for at least two weeks prior to protein C testing. Decreased concentrations of protein C are also associated with liver disease, vitamin K deficiency, acute thrombosis, and DIC. Increased protein C concentrations may be observed in nephrotic syndrome, pregnancy, and with estrogen therapy.

Reference range updated 9/22/2020.
Methodology:
Activity detection by chromogenic substrate.
Sample Processing:
Centrifuge within four hours of draw time.
Separate plasma into plastic container and cap (glass is not acceptable).
Centrifuge a second time to ensure platelet poor plasma and separate plasma into a new, labeled plastic tube, cap.
Sample Storage:
Freeze specimen immediately.
Transport Instructions:
Place labeled specimen into zip-lock type biohazard bag; seal bag.
Place packing list into outside pocket of bag.
Place dry ice on top of specimen in Styrofoam container.
CPT Code:
85303