von Willebrand factor multimers
Last updated: Thursday, 25, March, 2004
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4.5 mL blood added to 0.5 mL citrate or 5 mL blood in EDTA.
Crossed immunoelectrophoresis; SDS-agarose electrophoresis with autoradiography or enzyme-linked antibody staining.
Characterisation of patients with definite or highly probable von Willebrand’s disease into subtypes (that is, 1, 2, 3 or platelet-type VWD).
May also be useful when assessing VWD defects of genetic significance and as a guide to management.
Multimers are not used as a screening test for von Willebrand disease.
The findings are interpreted together with the personal and family history, and the levels of VWF by quantitative assays.
Type 1 VWD is a quantitative disorder of VWF (usually desmopressin responsive). These patients have normal VWF multimeric profiles but a lower overall intensity of apparent VWF by multimer testing, depending on the severity of the disorder.
Type 3 VWD (desmopressin unresponsive) is a total quantitative disorder of VWF and these patients generally have VWF undetectable by multimeric profile.
In Type 2 VWD there is an abnormality in the multimeric structure of VWF leading to reduced (ristocetin-induced) binding to platelets (Type 2A) or enhanced binding to platelets (Type 2B). Desmopressin responsiveness is variable in Type 2A.
In pseudo- or platelet-type VWD the large multimers of VWF are absent. Desmopressin and infusion of plasma are contraindicated as their use is associated with thrombocytopenia.
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Sadler JE. Thromb Haemost 1994: 71; 520-525.