FIGURE 2.

OSA/CSA ratio for different FVIII replacement products. Freshly prepared FVIII‐immunodepleted plasma samples (Roche Diagnostics International Ltd) spiked with FVIII recombinant products from Batch #2 were measured using both the OSA and CSA. The ratio for each FVIII replacement product was calculated with OSA and CSA results of samples adjusted to 5 IU/dL, 20 IU/dL, 60 IU/dL and 100 IU/dL FVIII activity, according to their labelled potency. The grey box indicates the minimum and maximum OSA/CSA ratios of native patient samples (N = 37) across a range of 4.24–102.00 IU/dL FVIII activity (measured using the OSA). CSA, chromogenic substrate assay; FVIII, factor VIII; HA, haemophilia A; OSA, one‐stage clotting assay