Diagnosis of Inherited von Willebrand Disease: A Clinical Perspective

Challenges in defining type 2M von Willebrand disease: results from a Canadian cohort study

“…Although this assay has been felt by some to be the most useful for the diagnosis of VWD [19], we have found significant variability in the results of this test in Canada using the platelet aggregation method. This variability becomes even more problematic when the required discrepancy for type 2M VWD between the VWF:RCo and VWF:Ag is not extreme.…”

“…These criteria include: excessive mucocutaneous bleeding (defined as the occurrence of one or more significant mucocutaneous bleeding symptoms by the tertiary care Inherited Bleeding Disorders Clinic who enrolled the patient) and VWF:Ag and/or VWF:RCo between 0.05 and 0.50 IU mL -1 on at least two occasions and mean RCo/Ag ratio < 0.6 and no loss of HMW multimers. Although an RCo/Ag ratio < 0.7 is often used to define type 2M VWD [19,20], on the basis of previous experience with the VWF:Ag and VWF:RCo assays within our laboratory, we have used a more stringent RCo/Ag ratio of < 0.6 to define type 2M disease in this study. The absence of a positive family history was not an exclusion criterion.…”

Diagnosis of platelet-type von Willebrand disease by flow cytometry

“…Ristocetin induced platelet aggregation (RIPA) is enhanced, plasma von Willebrand factor antigen (VWF:Ag) is normal or mildly reduced while von Willebrand factor activity is reduced, resulting in a low VWF:activity/VWF:Ag ratio. Given the clinical and laboratory similarities, patients with PT-VWD are often wrongly diagnosed as type 2B VWD 6,7 and the real prevalence of PT-VWD is therefore probably underestimated.…”

Investigating people with mucocutaneous bleeding suggestive of primary hemostatic defects: a low likelihood of a definitive diagnosis?

“…As noted, there are several possible options for undertaking a clinical bleeding review. [1][2][3][4][5][6]9,10 In the study by Quiroga et al, 2 the patients were interviewed by the same investigator using a standardized questionnaire, modified to assess mainly mucous and skin bleeding. The interviewer recorded the current and past bleeding episodes independently of the age at consultation, and the most frequent and typical symptoms were scored from 0 to 4, according to the frequency, duration, recurrence, and need and type of therapy.…”

“…[1][2][3][4][5][6][7][8] The clinician also initially needs to determine whether the presentation represents a congenital or acquired disorder, and whether it appears to be predominantly of primary or secondary hemostasis. There are currently several possible options with regards to the clinical bleeding review.…”