An international collaborative study to assign value for Total Factor XIII‐B Subunit Antigen to the WHO 1st International Standard for Factor XIII Plasma, (02/206): Communication from the ISTH SSC Subcommittee on Factor XIII and Fibrinogen. (30th November 2021)

• Record Type: Journal Article
• Authors: Raut, Sanj; Katona, Éva; Riches‐Duit, Andrew; Coxon, Carmen; Muszbek, László; Schroeder, Verena; Rigsby, Peter
• Is Part Of: Journal of thrombosis and haemostasis. Volume 20:Number 2(2022)
• Page Start: 525
• Page End: 531
• Publication Date: 2021-11-30
• Subjects: Factor XIII -- FXIII‐B subunit -- International Unit -- monoclonal antibody -- WHO International Standard; Thrombosis -- Periodicals; Hemostasis -- Periodicals; Blood coagulation disorders -- Periodicals; 616.1
• DOI: 10.1111/jth.15596
• Languages: English
• ISSNs: 1538-7933

Abstract

Abstract: Background: Factor XIII (FXIII)‐B subunit measurements are required for the diagnosis and characterization of the type of FXIII deficiency. Furthermore, therapy for FXIII‐A deficiency with recombinant FXIII (rFXIII‐A) relies on available FXIII‐B. Objective: To carry out a collaborative study to calibrate and assign value to the current WHO 1st International Standard (IS) FXIII Plasma for Total FXIII‐B subunit, relative to locally collected normal plasma pools. Methods: 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. Nine data sets were received from seven 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. Results: Combination of results produced an overall mean of 0.98 units/mL with an inter‐laboratory variability (geometric coefficients of variation – GCV%) of 18.3% [95% confidence interval: 0.86–1.11]. Real‐time and bench stability studies indicated good stability and preservation of the FXIII‐B subunit analyte in the WHO 1st IS FXIII Plasma (02/206). Conclusion: Following agreement by study participants, ISTH/SSC Experts, WHO‐ISTH Liaison Group and the SSC Board, the WHO/ECBS established the current WHO 1st IS Factor XIII plasma (NIBSC code 02/206) by additionally assigning it with a Total FXIII‐B subunit antigen value of 0.98 IU/ampoule, in October 2019.