Hemostasis Reference Laboratory

Protein C (Activity)

• Transaction Code: 3230-02
• CPT Code (Suggested): 85303

Protein C is a circulating proenzyme that, upon activation, inhibits coagulation by enzymatically inactivating factors Va and VIIIa. Functional Protein C level is measured using a clotting-based assay in which snake venom-activated protein C prolongs the chromogenic activity of activated clotting factors by inactivating factors Va and VIIIa. Hereditary Protein C deficiency is an autosomal dominant condition associated with a tendency toward venous thromboembolic disease. It is associated with warfarin-induced skin necrosis. Homozygous cases have neonatal purpura fulminans. Acquired protein C deficiency can occur secondary to vitamin K deficiency, warfarin therapy, liver disease and disseminated intravascular coagulation (DIC). Protein C has a short half-life in circulation, comparable to factor VII.

• Sample Required: 0.5 ml frozen plasma x4 or (2) 3.2% sodium citrated tubes, 5 ml each.
• See Sample Requirements when ordered with other tests.
• Normal Range: 60-140%
• Analytic Time: Within 5 working days