Protein C is a Vitamin K dependent anticoagulant protein which normally circulates as an inactive zymogen. Following activation, Protein C inactivates Factors V and VIII, prolonging the clotting time.
» The test uses Protac®, a direct Protein C activator, and an aPTT reagent to activate both Protein C and the contact factors of the intrinsic pathway
» The clot time of normal plasma is very long, while that of Protein C deficient plasma is essentially the same as the aPTT clot time
» When patient plasma is mixed with Protein C deficient plasma, the prolongation of the clotting time is directly proportional to the amount of Protein C activity in the patient plasma