The combination of emicizumab and recombinant factor VIII in plasma: Which assays can we use for accurate measurement?

Modified OSA and human FX CSA could not distinguish between rFVIII or emicizumab. The presence of both emicizumab and rFVIII increased thrombin generation to normal levels compared to each drug alone. Bovine FX CSA can be used to accurately determine FVIII activity of rFVIII in plasma which also contains emicizumab.