100 Years of von Willebrand Disease (VWD): Comparison of Historical and Contemporary von Willebrand Factor (VWF) Activity Assays in the Laboratory Identification of VWD.

INTRODUCTION: von Willebrand disease (VWD) is a prevalent bleeding disorder resulting from deficiencies and/or defects in von Willebrand factor (VWF). Accurately diagnosing VWD, particularly distinguishing between qualitative defects (types 2A, 2B, 2 M, and 2N) and quantitative defects (types 1 and 3), poses challenges that have significant implications for management and treatment strategies.

AIM: To describe latest contemporary findings from our geographic region for laboratory-based testing.

METHODS: This report outlines the most recent Australasian experience, drawing on data from the Royal College of Pathologists of Australasia (RCPA) Quality Assurance Program (QAP) specifically related to VWF testing within their VWD test module. We report outcomes from the past 4 years of distributed samples (n = 16), comprising normal (n = 3), type 1 VWD (n = 4), type 2A VWD (n = 4), 2B VWD (n = 2), type 2 M VWD (n = 2) and a factor VIII deficient plasma (n = 1), supplemented with historical program experience since 1998.

RESULTS: Among testing methods, VWF:RCo and VWF:GPIbM exhibited the highest variability and error rates, with discrepancies far greater than those observed with VWF:CB and chemiluminescence-based procedures. Laboratories performing 4-test panels including a VWF:CB produced far fewer errors in VWD classification than those performing 3-test panels.

CONCLUSION: These findings shed light on the factors contributing to elevated error rates in VWD diagnosis, indicating that certain assays and methodologies significantly outperform others.