COMPARISON OF THE CHROMOGENIC AND ONE-STAGE ASSAYS FOR FACTOR IX

一期凝血试验是最广泛应用的基础 凝血因子IX活性测定方法。它是基于 用加入法修正固定缺陷血浆的凝血时间 当然是FIX。最近，一种新的FIX检测方法已经被开发出来 包括在FXIa和FX的制剂中添加FIX。这个 添加的固定量可以从一个解离的速率确定 Xa因子的显色底物。我们已经进行了一次正式的 凝血法和发色法测定血清白蛋白的比较 凝血因子IX的效力浓缩。化验方法的多重比较 使用CBER当前的FIX标准FN2与当前的WHO标准， 84/618，证明了两种方法的等价性。Fn2的值 凝血法为9.3，显色法为9.1。 提交给CBER的多批凝血因子IX浓度的比较 测试表明，两种方法之间存在显著差异 一些浓缩液。这种分歧可以在一定程度上减少，当 显色分析采用动力学方法，而不是使用终点 方法。进一步的比较研究正在进行中。

The one-stage clotting assay is the basis for the most widely used method for determining factor IX activity. It is based on the correction of the clotting time of fIX deficient plasma by the addition of fIX. Recently, a new assay for fIX has been developed that assay involves the addition of fIX to a preparation of fXIa and fX. The amount of fIX added can be determined from the rate of cleavage of a chromogenic substrate by factor Xa. We have undertaken a formal comparison of the clotting and chromogenic assays for determining potency of factor IX concentrates. Multiple comparisons of the assays using CBER's current fIX standard, FN2 versus the current WHO standard, 84/618, demonstrated equivalence of the two methods. The value of FN2 by clotting assay was 9.3 and 9.1 for the chromogenic assay. Comparisons of multiple lots of factor IX concentrates submitted to CBER for testing indicated significant disagreement between the methods for some concentrates. This disagreement could be somewhat reduced when the chromogenic assay was read kinetically rather than using the endpoint method. Further comparative studies are in progress.