Von Willebrand factor assay proficiency testing. The North American Specialized Coagulation Laboratory Association experience.

摘要: We evaluated the accuracy and precision of von Willebrand disease (vWD) testing performed by up to 50 North American Specialty Coagulation Laboratories from 2004 through 2009, using proficiency samples healthy subjects (n = 7) patients with type 1 vWD or 2 3). analyzed 2,212 submitted results. Precision was highest for factor (vWF) antigen assays (coefficient variation, 14%), which were predominantly latex immunoassays, lowest ristocetin cofactor 28%), increasingly replaced collagen binding immunofunctional methods during 6-year evaluation period. Overall interpretation error rates ranged 3% normal samples, 28% vWD, 60% vWD. Type correctly identified all laboratories binding/antigen ratios but only one third cofactor/antigen immunofunctional/antigen ratios. In 27% (12/45) vWF multimer analysis, ranging 7% 22%.