Standardization of assays of factor VIII and factor IX.

T W Barrowcliffe
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引用次数: 8

Abstract

The development of international standards over the last 15-20 years has led to improved interlaboratory agreement on assays of factor VIII and factor IX. In the most recent international collaborative study, the coefficient of variation for one-stage assays (26 laboratories) was 5.6%. However, in quality assurance surveys, carried out in the UK and USA, agreement between laboratories is much less good, with coefficients of variation ranging from 30% to over 50%. Improvements in agreement between clinical laboratories could be obtained by increasing the amount of testing on each sample, especially the number of dilutions, and reducing the number of reagent systems used. A large number of laboratories now use immunodepleted plasmas instead of congenitally deficient plasmas as substrates for one-stage assays. These plasmas may give satisfactory assays, but many of them have not been thoroughly evaluated in comparison with congenitally deficient plasma. In assessment of potency of very high purity (VHP) factor VIII concentrates, some immunodepleted plasmas were found to give lower potencies than hemophilic plasma. This is partly due to the fact that VHP concentrates contain little or no von Willebrand factor (vWF), and most immunodepleted plasmas are also deficient in vWF. In recent collaborative studies, assays of VHP factor VIII concentrate were much more variable, both within and between laboratories, than assays of intermediate purity concentrates. Standardization of these new products will require careful attention to methodological detail.

因子VIII和因子IX测定的标准化。
在过去的15-20年里,国际标准的发展导致了因子VIII和因子IX测定的实验室间协议的改善。在最近的国际合作研究中,一级检测(26个实验室)的变异系数为5.6%。然而,在英国和美国进行的质量保证调查中,实验室之间的一致性要差得多,变异系数从30%到50%以上不等。临床实验室之间的一致性可以通过增加对每个样品的测试量,特别是稀释次数,以及减少所用试剂系统的数量来获得。许多实验室现在使用免疫缺失的血浆代替先天缺陷的血浆作为底物进行一期检测。这些血浆可能提供令人满意的检测结果,但其中许多尚未与先天性缺陷血浆进行彻底的评估。在评估非常高纯度(VHP)因子VIII浓缩物的效力时,发现一些免疫缺失血浆的效力低于血友病血浆。这部分是由于VHP浓缩物含有很少或不含血管性血友病因子(vWF),而且大多数免疫缺失的血浆也缺乏vWF。在最近的合作研究中,VHP因子VIII浓缩物的测定在实验室内部和实验室之间都比中间纯度浓缩物的测定变化更大。这些新产品的标准化需要仔细注意方法上的细节。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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