1 research outputs found
Analytical variation in factor VIII one-stage and chromogenic assays: Experiences from the ECAT external quality assessment programme
Background: Both one-stage (OSA) and chromogenic substrate assays (CSA) are used to measure factor VIII (FVIII) activity. Factors explaining analytical variation in FVIII activity levels are still to be completely elucidated. Aim: The aim of this study was to investigate and quantify the analytical variation in OSA and CSA. Methods: Factors determining analytical variation were studied in sixteen lyophilized plasma samples (FVIII activity <0.01-1.94Â IU/mL) and distributed by the ECAT surveys. To elucidate the causes of OSA variation, we exchanged deficient plasma between three company set-ups. Results: On average, 206 (range 164-230) laboratories used the OSA to measure FVIII activity and 30 (range 12-51