VWF assays in type 1 VWD subjects. Results for the VWF:Ag, VWF:RCo, and VWF:IbCo ELISA for 107 type 1 VWD subjects (all with VWF:Ag ≤ 50) enrolled in the ZPMCB-VWD. The line indicates the mean for each assay. All VWF:RCo values reported as less than 10 IU/dL are graphed at 10 IU/dL for visualization purposes.