Q: Why Heparin is added to Prothrombin Complex Concentrates (PCC)?

Answer:  PCC are produced by ion-exchange chromatography from the cryoprecipitate supernatant of large plasma pools. It may contain either three-factor (i.e., factors II, IX and X) or four-factor (i.e., factors II, VII, IX and X) concentrates with a final overall clotting factor concentration approximately 25 times higher than in normal plasma. To prevent activation of these factors, most PCC contain heparin. 

                             

References:

1. Hellstern P. Production and composition of prothrombin complex concentrates: correlation between composition and therapeutic efficiency. Thromb Res. 1999;95:S7–12.

2. Schulman S, Bijsterveld NR. Anticoagulants and their reversal. Transfus Med Rev. 2007;21:37–48.