The purpose of this study is to improve the investigators ability to diagnose von Willebrand Disease (VWD), a common inherited bleeding disorder. This study will look at a new screening blood test used to determine if a person has VWD. This new screening blood test can determine a diagnosis more rapidly than current blood tests. Also this test could be available at local hospital labs rather than require samples to be sent to bigger more specialized labs.

This investigation will be a prospective, multicenter trial to validate the clinical utility of a novel screening assay as a diagnostic screening assay for VWD variants: Type 1C, 2A, 2B, 2M and 2N. Once the subject is enrolled into the study, a minimum of 0.5ml of citrated plasma will be collected and analyzed at the Bleeding and Clotting Disorders Institute Laboratory in Peoria Illinois. Results will be collected: phenotype function profiles will be determined, statistically analyzed and compared to the qualitative data from Blood Center of Wisconsin. Data is expected to correlate as previously shown in prior studies and will confirm the utility of this assay.

Inclusion Criteria:

• New subjects undergoing evaluation for the diagnosis of VWD determined to have a VWF:Ag or VWF: RCo < 50 IU/dl and or a VWF:RCo/VWF:Ag of <0.7. Also subjects will be included if Type 2 N VWD is clinically suspected

Exclusion Criteria:

• Those subjects whose lab results do not meet the inclusion criteria

New subjects undergoing evaluation for the diagnosis of VWD that are determined to have VWF:ag or VWF:RCo <50 IU/dl and or a VWF:RCo/VWF:ag ratio of <0.7. Also subjects will be included if Type 2N VWD is suspected