[Effect of substrate and diluent for factor VIII activity in highly purified factor VIII concentrate and patient plasma infused factor VIII concentrate].
We studied the difference between congenital factor VIII deficient plasma and factor VIII immuno-depleted plasma on the effect of pre-dilution for factor VIII activity determined by the one-stage assay. When standard curves of one-stage assay for factor VIII: C by GEORGE KING factor VIII deficient plasma (frozen at -80 degrees C), BEHRING factor VIII deficient plasma (lyophilized), DADE factor VIII depleted plasma (lyophilized, von Willebrand factor antigen 0.2 U/ml) and DADE factor VIII depleted plasma (lyophilized, von Willebrand factor antigen 1.0 U/ml) were compared, the difference between the clotting times for 100% and 6.25% of activity in each reagent were 39.5, 29.5, 25.0, 23.0 seconds respectively. Potency values in concentrates without albumin or von Willebrand factor showed a discrepancy between pre-dilution in Owren-Koller buffer and pre-dilution in factor VIII deficient plasma. Potencies of those products pre-diluted in Owren-Koller buffer were 40-60% lower than potencies pre-diluted in factor VIII deficient plasma. These results showed substrate and pre-diluent must be chosen carefully for the accurate assay of factor VIII activity in vitro for the highly purified factor VIII concentrates.
Takahashi
I
I
Japanese Red Cross Aichi Blood Center, Seto.
Furuta
M
M
Mizuno
S
S
Takamatsu
J
J
Kamiya
T
T
D000328:Adult; D002021:Buffers; D005169:Factor VIII / Q000032:analysis*; D006467:Hemophilia A / Q000097:blood*; D006801:Humans; D007201:Indicator Dilution Techniques; D008297:Male; D013379:Substrate Specificity
D002021:Buffers; D005169:Factor VIII