Glycoprotein 1bM assay and von Willebrand disease: a change in diagnosis.
TL;DR
The use of the VWF:GP1bM assay may improve the ability to accurately diagnose VWD, prompting a change in diagnosis and emphasizing the assay's critical role in optimizing patient care.
Abstract
The diagnosis of von Willebrand disease (VWD) is complicated by limitations of traditional laboratory tests, such as the VWF ristocetin cofactor (VWF:RCo) assay. Newer assays, such as the VWF glycoprotein 1bM (VWF:GP1bM) assay, are more reliable and not affected by the D1472H polymorphism; thus, current hematology societal guidelines recommend these newer assays for diagnosing VWD. This study aims to perform a descriptive analysis of the impact of the VWF:GP1bM assay on the diagnosis of VWD among previously diagnosed patients at the Hemophilia Center of Western Pennsylvania. This retrospective chart review included patients with a historical diagnosis of VWD, in part based on VWF:RCo activity, VWF:GP1bM activity performed separate from and subsequent to the historical diagnosis of VWD, and 18 years of age at the time of data abstraction. The primary outcome was a change in historical VWF:RCo assay-based diagnosis to an alternative current VWF:GP1bM assay-based diagnosis. This study analyzed 138 patients with a mean age of 36.7 years. The mean VWF:RCo activity, 0.56 IU/ml, was lower than the mean VWF:GP1bM activity, 0.73 IU/ml, P < 0.001. The VWF:GP1bM assay led to a change in diagnosis in 42.8% of patients, including 26.1% of patients with no bleeding disorder. The presence of the D1472H polymorphism was associated with 10.6 greater odds, P < 0.01, of a change in diagnosis. The use of the VWF:GP1bM assay may improve the ability to accurately diagnose VWD, prompting a change in diagnosis and emphasizing the assay's critical role in optimizing patient care.