The 'in vivo' survival characteristics of factor VIII procoagulant antigen (VIII:C Ag) in haemophilia A subjects.

Initial half disappearance times and biological half-lives were determined for factor VIII procoagulant antigen (VIII:C Ag) and compared with VIII procoagulant (VIII:C) survival for each of two commercial concentrates, transfused into seven severe (less than 1 i.u./dl) non-bleeding haemophiliacs. The results show that VIII:C Ag has similar half disappearance and biological half-life to that of factor VIII:C. The relevance of these results to recently published findings is discussed.