Factor VIII procoagulant and antigen content of antihemophilic factor (AHF) concentrates

Antihemophilic factor concentrates from six manufacturers were studied for factor VIII procoagulant and antigen content. Marked lot-to-lot differences were found in the factor VIII antigen:procoagulant ratio. The average antigen content was 2.33 times that of procoagulant activity in 21 lots studied, indicating a significant loss of activity during the fractionation process.