VWF multimer analysis. VWF multimer analysis was performed on citrated plasma samples using the Hydrasys 2 with a SDS agarose gel (Hydragel 5 von Willebrand multimers), according to the manufacturer's instructions. The stained gel (left) demonstrates a reduced amount of high-molecular-weight multimers (HMWMs) and intermediate-molecular-weight multimers (IMWMs) and a marked increase in unmultimerized VWF dimer (labeled D) in the patient sample compared to the normal pooled plasma control (left). This pattern contrasts with the classic type 2A pattern characterized by selective loss of HMWMs, as can be seen in the accompanying gel (2A). A densitometric analysis of the electrophoretic gel (right) emphasizes the predominance of unmultimerized dimer in the electrophoretic pattern of patient VWF (magenta curve) compared with normal plasma (black curve). The percentages of low-molecular-weight multimers (LMWMs), IMWMs, and HMWMs in the patient’s plasma sample are shown below the densitometry curves. 2A, plasma sample from patient with classic type 2A von Willebrand disease; C, pooled normal plasma control; Pt, plasma sample from current patient.