Protein C Deficiency Profile

Clinical Use

Order Test

Use

Confirmation and characterization of protein C deficiency

Special Instructions

Not provided.

Limitations

Patients with heterozygous protein C deficiency may exhibit low normal PC levels. Warfarin treatment reduces vitamin K-dependent factors including PC. Elevated factor VIII levels during acute phase reaction can normalize aPTT, effectively reducing PC levels. PC levels may falsely appear lowered in individuals with factor VLeiden mutation. Testing is not recommended during immediate convalescent periods after thrombotic events due to potential PC depletion. Heparin therapy up to 1 unit/mL does not impact PC levels, but thrombin inhibitors like hirudin or argatroban do. Results interpretation should consider these variations.

Test Details

Methodology

Immunoassay (Multiplex Protein Panel)

Biomarkers

LOINC Codes

Order Codes

27820-0 - Prot C Ag Act/Nor PPP IA

Result Codes

27820-0 - Prot C Ag Act/Nor PPP IA
27818-4 - Prot C Act/Nor PPP Chro

Result Turnaround Time

2-4 days

Specimen

Plasma

Volume

1 mL (each tube)

Minimum Volume

Not provided

Container

Blue-top (sodium citrate) tubes (2 tubes)

Collection Instructions

Citrated plasma samples should be collected by double centrifugation. Ensure a proper blood to anticoagulant ratio by filling tubes completely. Mix sample gently at least six times. Centrifuge for 10 minutes, then use a plastic pipette to transfer plasma. Deliver to a Labcorp PP transpak frozen purple tube, and freeze immediately.

Patient Preparation

Avoid warfarin (Coumadin) therapy for two weeks and heparin therapy for two days prior to the test. Do not draw from an arm with a heparin lock or heparinized catheter.