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Little discrepancy between one-stage and chromogenic FVIII/IX assays in a large international cohort of persons with non-severe hemophilia A and B

Zwagemaker, Anne-Fleur, Kloosterman, Fabienne R., Gouw, Samantha C., Boyce, Sara, Brons, Paul, Cnossen, Marjon H., Collins, Peter W. ORCID:, Eikenboom, Jeroen, Hay, Charles, Hengeveld, Rutger C. C., Jackson, Shannon, Klopper-Tol, Caroline A. M., Kruip, Marieke J. H. A., Laros-van Gorkom, Britta, Male, Christoph, Nieuwenhuizen, Laurens, Shapiro, Susan, Fijnvandraat, Karin, Coppens, M. and on behalf of the DYNAMO study group 2023. Little discrepancy between one-stage and chromogenic FVIII/IX assays in a large international cohort of persons with non-severe hemophilia A and B. Journal of Thrombosis and Haemostasis 21 (4) , pp. 850-861. 10.1016/j.jtha.2022.11.040

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Background Accurate measurements of coagulation factor activity form an essential part of hemophilia management and are performed by the one-stage or chromogenic assay. Current literature suggests that approximately one-third of persons with non-severe hemophilia A exhibit assay discrepancy, although with a high variability between studies. Such data are scarce in non-severe hemophilia B. Objective To investigate the extent of FVIII/IX one-stage and chromogenic assay discrepancy in moderate and mild hemophilia A and B. Methods Persons with previously diagnosed non-severe hemophilia A and B with a factor level 2-35 IU/dL were included from the international DYNAMO cohort study. Central measurements of the FVIII and FIX activity levels were performed by the one-stage and chromogenic assay. Relative and absolute discrepancy definitions were used with the ISTH-SSC proposed ratio of >2.0 or <0.5 being the primary outcome. Discrepancy was also evaluated in a subgroup of 13 persons with mutations previously associated with discrepancy (≥3 cases reported in literature). Results A total of 220 persons were included of whom 3 (1%) showed assay discrepancy: 2/175 hemophilia A and 1/45 hemophilia B. Six persons (3%) exhibited an absolute difference >10 IU/dL between the assay results. Also with more lenient definitions over 90% of participants (n=197) had no discrepant results. Only 1 of 13 persons with a mutation previously associated with discrepancy had significant assay discrepancy. Conclusion Little assay discrepancy was observed despite the presence of mutations previously associated with discrepancy, suggesting that the presence and magnitude of assay discrepancy is largely determined by laboratory variables.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Medicine
Additional Information: License information from Publisher: LICENSE 1: Title: This article is under embargo with an end date yet to be finalised.
Publisher: Wiley
ISSN: 1538-7836
Date of First Compliant Deposit: 9 January 2023
Date of Acceptance: 28 November 2022
Last Modified: 22 Dec 2023 18:28

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