This study was performed in part to assess the utility of VWF activity/Ag ratios to capture type 2 VWD cases, particularly relevant in the age of the latest diagnostic VWD guidelines [2], which recommend use of newer VWF:GPIbB assays (VWF:GPIbM or VWF:GPIbR) ahead of classical VWF:RCo since they would likely yield lower variability, better low VWF level sensitivity, and improve VWD diagnosis reliability. This evidence concerns the gene VWF and von Willebrand disease 2.