Protein C antigen in prothrombin complex concentrates: content, recovery and half life.

Protein C, a potent anticoagulant, has been detected in large amounts in some prothrombin complex concentrates (PCC). We extended these findings to eight PCC commercially available in West Germany detecting 0.82 to 1.92 plasma equivalent units of protein C antigen (PC:Ag) per unit factor IX. Infusion of PCC in four patients on stable oral anticoagulation resulted in a recovery of 58.6 +/- 10.9%. Estimated from the decrease in plasma levels of PC:Ag half life was 7.9 +/- 0.6 h.