STANDARDS FOR ASSAY OF VON WILLEBRAND FACTOR--A COLLABORATIVE STUDY

进行了一项多实验室合作研究，以评估 使用血浆标准品测定von Willebrand的可行性 血管性血友病因子浓缩物和因子VIII的因子含量 浓缩物。 13个实验室检测了6种浓缩物中的冯 维勒布兰德因子抗原、瑞斯托康辅因子活性和多聚体 使用世界卫生组织血浆标准品的因子含量 VIII/von Willebrand因子，87/718，作为标准。 只有少数几项检测 由于非并行性或非线性而无效。 显著 实验室间和试验间差异，发现两个冯 维勒布兰德因子抗原和瑞斯托康辅因子活性。 有 实验室之间在以下方面的一致性普遍良好： 制剂中的多聚体含量。 关于试验有效性， 血浆标准品可适用于浓缩制剂的含量测定 血管性血友病因子

A multilaboratory collaborative study was undertaken to assess the feasibility of using a plasma standard for assaying the von Willebrand factor content of von Willebrand factor concentrates and of factor VIII concentrates. Thirteen laboratories tested six concentrates for von Willebrand factor antigen, ristocetin cofactor activity, and multimer content using the World Health Organization plasma standard for factor VIII/von Willebrand factor, 87/718, as a standard. Only a few assays were invalid because of nonparallelism or nonlinearity. Significant interlaboratory and interassay differences were found for both von Willebrand factor antigen and ristocetin cofactor activity. There was generally good agreement between the laboratories with respect to multimer content in the preparations. With respect to assay validity, a plasma standard could be suitable for assaying concentrated preparations of von Willebrand factor.