Von Willebrand Factor (VWF) multiplex activity assay differentiation of type 1 von Willebrand Disease (VWD) and variant VWD

Abstract

AbstractIntroductionVWD diagnosis is challenging requiring multiple VWF activity tests using many individual assays. We have developed an ELISA‐based VWF Multiplex Activity Assay (VWF‐MAA) to address this concern; however, the ability of the VWF‐MAA to discriminate between type 1 VWD, variant VWD, and normal subjects has not been evaluated.AimTo evaluate the VWF‐MAA and its ability to differentiate between type 1 VWD, variant VWD and normal subjects in individuals undergoing an initial laboratory evaluation for bleeding.MethodsA total of 177 plasma samples from the Zimmerman Program: Comparative Effectiveness in the Diagnosis of VWD were evaluated from 11 centres across the US and Canada. The VWF‐MAA was compared to Versiti Blood Research Institute (VBRI) and Local Center (LC) assigned VWD diagnosis.ResultsOverall, 129/177 (72.9%) were correctly assigned as normal (non‐VWD), type 1, or variant VWD compared to the VBRI assigned diagnosis. VWF‐MAA assigned non‐VWD accurately in 29/57 (50.9%) samples, and type 1 VWD accurately in 93/110 (84.6%) samples. Considering LC diagnosis where there was agreement with VWF‐MAA and not VBRI diagnosis, type 1 VWD was accurate in 105/110 (95.5%) samples. Bland‐Altman analysis demonstrated good correlation between laboratory methods. VWD, types 2A, 2B, 1C VWD were also assigned by the VWF‐MAA.ConclusionsWe demonstrate that the VWF‐MAA has utility in differentiating type 1 VWD, variant VWD and normal subjects in individuals undergoing an initial laboratory evaluation for bleeding.