2022 Volume 71 Issue 1 Pages 67-72
The one-stage assay (OSA) for factor VIII activity (FVIII:C) measurement has been widely used, but its accuracy depends on the composition of APTT reagents. Therefore, we conducted a basic study of the coagulation FVIII:C quantification reagent “Revohem FVIII synthetic substrate” used in chromogenic assay, and compared this chromogenic assay with OSA using archived plasma samples. As a result, the simultaneous reproducibility CV was from 0.95 to 1.14% and the daily reproducibility CV was 2.15 to 4.13%. The correlations of CSA with the fivefold dilution of OSA and the 20-fold dilution of OSA were good (r = 0.99, y = 1.04x − 1.24; r = 0.99, y = 0.99x + 4.46, respectively). No interfering substances were observed. In a comparative study between CSA and OSA, there were discrepancies in the number of patients with LA positivity and those with hemophilia A under emicizumab therapy. From the above results, it can be said that the coagulation factor VIII quantification reagent “Revohem FVIII synthetic substrate” used in chromogenic assay is sufficiently compatible with tests routinely performed. CSA is less susceptible to LA and emicizumab than OSA.
