1. In vitro field study and worldwide survey assessing how clinical haemostasis laboratories analyse recombinant and plasma‐derived von Willebrand factor products.
- Author
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Turecek, Peter L., Ilk, Reinhard, and Gritsch, Herbert
- Subjects
VON Willebrand factor ,PATHOLOGICAL laboratories ,VON Willebrand disease ,BLOOD coagulation factor VIII ,DESMOPRESSIN ,FIELD research ,IN vitro studies - Abstract
Introduction: Several well‐established clinical laboratory methods are available to measure von Willebrand factor (VWF) in plasma samples, but few data are available on their use for analysing recombinant VWF (rVWF). Aim: To evaluate how clinical diagnostic laboratories analyse rVWF and plasma‐derived VWF (pdVWF) spiked in vitro into VWF‐deficient plasma using quantitative protein and functional assays of VWF. Methods: Human VWF‐deficient plasma samples were spiked with rVWF (vonicog alfa; Takeda) or pdVWF/factor VIII (pdVWF/FVIII; antihemophilic factor/VWF complex [human], CSL Behring), each at final concentrations of 1.0, 0.6, 0.2, 0.1 IU/mL VWF:ristocetin cofactor activity (VWF:RCo) according to labelled VWF activity. The ISTH SSC secondary coagulation standard was used as a control. Participating laboratories received three sets of these blinded aliquots. Mean results per assay were compared with the expected potency based on the labelled VWF:RCo activity. Results: Among 39 laboratories, the most commonly established assay was VWF:RCo; 22 laboratories reported data from 2214 tests. Despite a trend to lower values, VWF:RCo activities for rVWF were in agreement with target concentrations (71%–109%), whereas VWF:platelet glycoprotein Ib (VWF:GpIb) and VWF collagen‐binding activity (VWF:CB) assays gave high recoveries (up to 132% and 127%, respectively). In contrast, pdVWF/FVIII was substantially underestimated by VWF:GpIb and VWF:CB assays (56%–86% recoveries), whereas the VWF:RCo assay gave recoveries of 47%–112% for pdVWF/FVIII. Conclusion: The results of VWF assays used in clinical laboratories differ between rVWF and pdVWF, particularly for VWF:GpIb and VWF:CB assays. These differences may arise from the higher multimeric structure of rVWF compared to pdVWF. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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