[Factor VIII preparations of varying purity-examination of physico-chemical parameters (author's transl)].

Commerical preparations of cryoprecipitates, factor VIII concentrates of intermediate purity, and factor VIII concentrates of high purity were studied for their factor VIII related clotting- and platelet-aggregating activities as well as their content of factor VIII antigen. The ratios of the values obtained of these three parameters were used to determine the extent of inactivation of the factor in the preparations. By means of two-dimensional immunelectrophoresis and gel chromatography on Sepharose 4B, the preparations were tested for the presence of atypical factor VIII molecules. Investigations were made to qualify and quantify some of the concomitant proteins in the factor VIII preparations.