Toward a new paradigm for the identification and functional characterization of von Willebrand disease.

The diagnosis and functional characterization of von Willebrand disease (VWD) is challenging. There are inherent difficulties in both its identification and classification because of clinical uncertainty, the limitations in the test processes and test panels typically used by laboratories, and because the classification scheme does not always allow unequivocal assignment of any subtype. This article reviews current thoughts and alternatives to the classic approach of the classification and functional characterization of VWD. Of particular interest to this author is the utility of an extended core test panel that includes additional functional VWF assays, such as the collagen binding assay, and the potential for desmopressin (DDAVP) challenge to not only provide therapeutic information but also assist in the better characterization of individuals with defects or deficiencies in von Willebrand factor (VWF). The potential use of supplementary assays such as the PFA-100 and the VWF propeptide assay after DDAVP challenge is also worth noting.