Abstract
The U.S. College of American Pathologists (CAP) has conducted a focused study of the proficiency testing for von Willebrand disease (vWD) analysis from 2003 to 2005. This report summarizes the findings regarding the accuracy and precision of the various assays at different analyte levels, as well as the influence of the reference material used to construct the assay standard curve. The results show that testing of von Willebrand factor (vWF):antigen (vWF:Ag) and ristocetin cofactor activity (vWF:RCo) is reasonably accurate, with all-method mean values falling within 3.2 and 5.6%, respectively, of the International Society on Thrombosis and Haemostasis Secondary Coagulation Standard (lot 2) assigned values. vWF:Ag measurements are reasonably precise (all-method coefficients of variation [CVs] = 10.7 to 15.1%), even at lower levels of vWF. The highest precision was observed for immunoturbidometric assays (CVs, 6.3 to 9.7%). vWF:RCo measurements are less precise (all-method CVs, 23.3 to 30.9%). The reference materials used in the standard curves for immunoturbidometric vWF:Ag assays appear to have accurately assigned vWF values for the majority of commercial suppliers.
Original language | English |
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Pages (from-to) | 499-504 |
Number of pages | 6 |
Journal | Seminars in Thrombosis and Hemostasis |
Volume | 32 |
Issue number | 5 |
DOIs | |
State | Published - Jul 2006 |
Keywords
- Hemostasis testing
- Proficiency testing
- Quality assurance
- Quality control
- Von Willebrand disease (vWD)
- Von Willebrand factor (vWF)