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An international collaborative study to compare different von Willebrand factor glycoprotein Ib binding activity assays: the COMPASS‐VWF study
Author(s) -
Szederjesi A.,
Baronciani L.,
Budde U.,
Castaman G.,
Lawrie A. S.,
Liu Y.,
Montgomery R.,
Peyvandi F.,
Schneppenheim R.,
Várkonyi A.,
Patzke J.,
Bodó I.
Publication year - 2018
Publication title -
journal of thrombosis and haemostasis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.947
H-Index - 178
eISSN - 1538-7836
pISSN - 1538-7933
DOI - 10.1111/jth.14206
Subject(s) - von willebrand factor , medicine , ristocetin , von willebrand disease , platelet , immunology
Essentials New VWF activity assays are increasingly used but information on their comparability is limited. This is an ISTH SSC‐organized study (expert labs, 5 countries) to compare all available assays. VWF activity by six assays correlated well with each other. The new assays show improved characteristics ‐ minor differences are noted.Summary Background Several new assays have become available to measure von Willebrand factor ( VWF ) activity. The new assays appear to have improved performance characteristics compared with the old reference standard, ristocetin cofactor activity ( VWF : RC o), but information is limited about how they compare with VWF : RC o and each other. Methods The von Willebrand factor Subcommittee of the International Society for Thrombosis and Haemostasis ( ISTH ) Scientific and Standardization Committee ( SSC ) designed a collaborative study involving expert laboratories from several countries to compare available tests with each other and with VWF : RC o. Eight laboratories from five countries were provided with blinded samples from normal healthy individuals and well‐characterized clinical cases. Laboratories measured VWF activity using all tests available to them; data from six laboratories, not affected by thawing during transportation, are included in this study. Results All tests correlated well with VWF : RC o activity ( r ‐values ranged from 0.963 to 0.989). Slightly steeper regression lines for VWF :Ab and VWF : GPI bM were clinically insignificant. The new assays showed improved performance characteristics. Of the commercially available assays, the VWF : GPI bR using the AcuStar system was the most sensitive and could reliably detect VWF activity below 1 IU dL −1 . The lower limit of the measuring interval for the VWF : GPI bM and the VWF : GPI bR assays was in the 3–4 and 3–6 IU dL −1 range, respectively. Inter‐laboratory variation was also improved for most new assays. Conclusion All VWF activity assays correlated well with each other and the VWF : RC o assay. The slight differences in characteristics found in the COMPASS ‐ VWF study will assist the VWF community in interpreting and comparing activity results.