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July, 2018 Quick Question: Factor IX Assay Method

Here are the results of our July, 2018 Quick Question, “How do you measure factor IX therapy?”

  1. Clot-based factor assay (34) 83%
  2. Immunoassay (4) 10%
  3. Chromogenic substrate (3) 7%

We had 41 respondents. Although there are a few chromogenic substrate-based factor IX assays available worldwide, none has been approved by the US FDA, though two are marketed in the US for “research use only.” Conversely, there are a number of chromogenic factor VIII assays available, some of which are approved. In general, chromogenic substrate methodology provides for greater precision, and in the case of synthetic extended half-life therapeutic factor concentates, greater accuracy. Chromogenic substrate approaches are likely grow in popularity as these concentrates replace standard preparations.

Comments (1)
Bleeding Disorders
Sep 10, 2018 1:12pm

Hi George,

Hi George,
See Adcock DM, Strandberg K, Shima M, Marlar RA. Advantages, disadvantages and optimization of one-stage and chromogenic factor activity assays in haemophilia A and B. Int J Lab Hematol. 2018 . doi: 10.1111/ijlh.12877. [Epub ahead of print]. They actually discuss additional applications for chromogenic assays other than for new extended half life hemophilia therapies, such as for certain FVIII and FIX mutations in which there are discrepant results between clotting and chromogenic assays.

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