[Comparative protein chemistry studies on Factor VIII concentrates].

Large amounts of Factor VIII concentrates are required for the treatment of haemophiliacs. Two batches each of nine commercial preparations were examined for their in vitro properties. The parameters studied were Factor VIII coagulation activity (F VIII: C), ristocetin cofactor activity (F VIII R: CoF), the Factor VIII antigen content (F VIII R: Ag), fibrinogen, fibronectin and immunoglobulins. The preparations were also tested to determine their hepatitis A and B marker content. In none of the investigated concentrates compared to the data given by the manufacturers was a marked F VIII: C deficit. All the preparations showed higher values for F VIII R: Ag than for F VIII: C. Factor VIII concentrate HS was the only concentrate in which the fibrinogen concentration was below the detection limit and only small amounts of fibronectin and immunoglobulins were detected. In two of the nine preparations tested possible contamination with hepatitis B viruses was more or less ruled out by means of hepatitis serology.