WHO/BS/2019.2370 Collaborative Study to additionally assign value for Total Factor XIII-B Subunit Antigen to the WHO 1st IS for Factor XIII Plasma

Overview

A collaborative study was undertaken to value assign the current WHO 1st International Standard (IS) Factor XIII (FXIII) Plasma for Total FXIII-B subunit, relative to locally collected normal plasma pools.

Laboratories were instructed to use a validated method (specific ELISA antibodies provided) for assessment of Total FXIII-B subunit antigen potency. All laboratories used this method with one laboratory using an additional in-house method also. Nine (9) data sets were received from 7 laboratories (37 assays in total), which provided a total of 35 valid estimates for this new assignment. Total FXIII-B subunit estimates were calculated relative to locally collected normal plasma pools, using an arbitrary value of 1.00 unit of Total FXIII-B subunit per ml, for each pool.