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Toward a better personalization of treatment with EHL: when the laboratory matters!

With version 5.3 of WAPPS-Hemo, released today, we have introduced a new function that will improve our profiling of hemophilia patients treated with extended half-life (EHL) concentrates. Indeed, there is a little price to pay for enjoying the favourable PK of EHL’s, but the level in the blood cannot always be precisely measured with some specific reagents.

Until now we have assumed that WAPPS-Hemo users and your laboratories would know which are the approved reagents for use.  We will now ask you to specify which reagent your laboratory uses.  Following the pragmatic spirit of WAPPS-Hemo, once you have indicated the reagent for a concentrate, you will only need to only do it the first time.  Subsequently, your selection will automatically populate your screen until you change it. 

We understand you may not know which reagents your laboratory uses, and you may need to ask them laboratory for clarification.  They should be able to provide this answer quickly and this small effort on your part will have multiple benefits. 

  • the educational value for you and your laboratory regarding the importance of reagents
  • ensuring optimal accuracy for your PK estimates, tying your PK to the correct concentrate/reagent combination
  • it provides important information regarding the real impact of different reagents

We do suggest the recommended reagent, but you can still enter data regardless of the reagent you choose.  Over time, our modelling will learn the actual impact of using different reagents.  Of course, we encourage you to only use those recommended by the current guidelines.

Well, how does it work?

There are two ways:


When you click on “Add a PK study” you are presented with this screen, where traditionally the assay type (clotting/chromogenic) and the calibrator (generic/drug specific) are located.

If you select a EHL (Alprolix as an example), you will now be presented a list of reagents:


Srivastava, A, Santagostino, E, Dougall, A, et al. WFH Guidelines for the Management of Hemophilia, 3rd edition. Haemophilia. 2020: 26(Suppl 6): 1‐ 158.

Gray, E, Kitchen, S, Bowyer, A, et al. Laboratory measurement of factor replacement therapies in the treatment of congenital haemophilia: A United Kingdom Haemophilia Centre Doctors’ Organisation guideline. Haemophilia. 2020; 26: 6– 16.