Performance of two new automated assays for measuring von Willebrand activity: HemosIL AcuStar and Innovance.

ABSTRACT

The ristocetin cofactor activity assay (VWFRCo) is the reference method for assessing von Willebrand factor (VWF) activity but remains difficult to perform, and the coefficient of variation of the method is high (about 20-30%). This study evaluated and compared the performance for measuring the VWF activity of two newly commercialised assays [VWFAc Innovance (VWFAc) and VWFRCo Acustar (VWFRCo Acu)] with the reference VWFRCo aggregation in 123 pathological plasma samples. The correlation and concordance between both new tests (VWFRCo-Acu and VWFAc) and the reference VWFRCo were good. The results of the VWF activity to VWF antigen ratio were also comparable whatever the method for the classification of VWF deficiency in all patients. Our results showed that both new tests could replace the "gold standard" VWFRCo in aggregometry with several benefits they are fully automated, easier and faster to perform, better adapted to emergency situations if necessary.