WHO/BS/2017.2324 Proposed WHO Reference Reagent for Activated Blood Coagulation Factor X(FXa), Human

Overview

Approval was obtained from the Expert Committee on Biological Standardization of WHO to prepare a WHO Reference Reagent (RR) for Activated Blood Coagulation Factor X (FXa), Human. The RR is proposed as a replacement for the current Non-WHO Reference Material for FXa (75/595), of bovine origin. A candidate material was donated by a manufacturer and was formulated, lyophilized and coded 15/102. The proposed WHO RR was calibrated against 75/595 using a direct chromogenic assay with a potency estimate for 15/102 based on results from 12 independent assays from two laboratories. Intra-laboratory variability was low (GCV<4%) and laboratory GM estimates showed good agreement (6.5 and 6.8 units per ampoule). The overall geometric mean was used to potency assign the candidate RR (15/102), which was determined to be 6.7 units per ampoule.