Platelet‐dependent von Willebrand factor activity. Nomenclature and methodology: communication from the SSC of the ISTH

Bodó, Imre; Eikenboom, Jeroen; Montgomery, Robert R.; Patzke, Jürgen; Schneppenheim, Reinhard; Paola, Jorge Di

doi:10.1111/jth.12964

Cited by 125 publications

(138 citation statements)

References 57 publications

(62 reference statements)

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“…Innovance VWF Ac, performed at site 1, is a VWF:GP1bM type assay2 that utilizes two gain of function mutations to glycoprotein 1b (GP1b) in place of Ristocetin and platelets. The VWF:Ag and VWF Ac of multimer discrepant patients were confirmed on repeat.…”

Section: Discussionmentioning

confidence: 99%

“…VWF comprises subunits of variable size from the low molecular weight multimers (LMWM) to subunits of more than 50 in size, the high molecular weight multimers (HMWM). VWD is sub‐typed by the ratio of the activity (VWF Ac) to the concentration of protein (VWF antigen, VWF:Ag) 2. A VWF Ac/VWF:Ag ratio of >0.6 indicates a quantitative type 1 disorder.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of a semi‐automated von Willebrand factor multimer assay, the Hydragel 5 von Willebrand multimer, by two European Centers

Bowyer¹,

Goodfellow²,

Seidel³

et al. 2018

Research and Practice in Thrombosis and Haemostasis

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BackgroundThe phenotypic diagnosis of von Willebrand disease (VWD) is a multistep process with classification dependent on the quantification of von Willebrand factor (VWF) multimeric structure. VWF multimer analysis is a technically challenging, lengthy and non‐standardised assay, usually performed in specialist laboratories. Recently, a new semi‐automated multimer assay, the Hydragel 5 von Willebrand multimers (H5VWM) has become available.ObjectivesThis study, performed in two European centres, compared existing in‐house multimer assays to the H5VWM in individuals with and without VWD.ResultsOverall agreement of 91.1% was observed in 74 individuals with normal VWF levels, 57 patients grouped as type 1 VWD, 33 type 2A, 16 type 2B, 28 type 2M, 11 type 2N. Patients tested following Desmopressin or VWF concentrate, with thrombotic thrombocytopenic purpura and acquired von Willebrand syndrome were also evaluated. Many of the discrepancies between methods were in patients with genetic mutations linked to more than one type of VWD including p.R1374C/H and p.R1315C. Quantifiable multimer results were available within one working day. Densitometry improved the interpretation of the multimers with slight structural variations that were not apparent by visual inspection of the in‐house method.Conclusions5VWM was a rapid, sensitive, standardised assay which used existing technology and could be included as an initial screen of VWF multimers in a VWD diagnostic algorithm in conjunction with traditional multimer analysis.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evaluation of a semi‐automated von Willebrand factor multimer assay, the Hydragel 5 von Willebrand multimer, by two European Centers

Bowyer¹,

Goodfellow²,

Seidel³

et al. 2018

Research and Practice in Thrombosis and Haemostasis

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“…The name VWF:GPIbM refers to the use of GPIb rather than platelets and to the fact that the GPIb contains mutations (M) as per ISTH recommendations for VWF activity assay nomenclature 39. To properly evaluate VWF:GPIbM, results should be considered in context of VWF:Ag.…”

Section: Rise Of the Vwf:gpibm Assay (And Death Of The Vwf:rco?)mentioning

confidence: 99%

Current issues in diagnosis and treatment of von Willebrand disease

Keesler

Flood

2018

Research and Practice in Thrombosis and Haemostasis

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Essentials Classification of VWD includes quantitative (types 1 and 3) and qualitative (type 2) variants.New assays of VWF‐platelet binding may improve accuracy in diagnosis.Collagen binding represents an additional function of VWF not measured by current tests.Treatment options for VWD include desmopressin, plasma‐derived, and recombinant VWF. Clinically, von Willebrand disease (VWD) presents as mucosal bleeding caused by a decreased quantity or quality of von Willebrand factor (VWF). Diagnosis of VWD requires careful consideration of patient specific factors, bleeding symptoms, and laboratory results. Patients with borderline low VWF levels remain challenging, given that low VWF is not necessarily a guarantee of bleeding, but is present in many patients with symptoms, and treatment of low VWF may improve bleeding. Laboratory diagnosis of VWD is complex and no single test can determine the presence or absence of functional VWF. Historically, VWF binding to platelet GPIbα was measured by the ristocetin cofactor assay (VWF:RCo); a new assay using platelet GPIbα in the absence of ristocetin (VWF:GPIbM) is gradually replacing the VWF:RCo due to improved accuracy in diagnosis. VWF binding to collagen is a separate function, and requires specific testing to determine if a collagen binding defect is present. Regardless of these laboratory complexities, clinicians can empirically treat VWD to alleviate bleeding symptoms by raising VWF levels through desmopressin or VWF concentrate. Recombinant VWF is now available, but clinicians may need to add an initial dose of FVIII when treating emergency bleeds.

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“…18 Ligand binding assays were performed as previously described, including VWF binding to type III collagen (VWF:CB3), 16 VWF binding to type IV collagen (VWF:CB4), 19 and VWF binding to mutant platelet GPIb (VWF:GPIbM). 20,21 VWF propeptide (VWFpp) was measured to evaluate for VWF clearance defects. 22 Blood type was ascertained by reverse typing.…”

Section: Laboratory Evaluationmentioning

confidence: 99%

Clinical and laboratory variability in a cohort of patients diagnosed with type 1 VWD in the United States

Flood

Christopherson

Gill

et al. 2016

Blood

107

171

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Platelet‐dependent von Willebrand factor activity. Nomenclature and methodology: communication from the SSC of the ISTH

Cited by 125 publications

References 57 publications

Evaluation of a semi‐automated von Willebrand factor multimer assay, the Hydragel 5 von Willebrand multimer, by two European Centers

Evaluation of a semi‐automated von Willebrand factor multimer assay, the Hydragel 5 von Willebrand multimer, by two European Centers

Current issues in diagnosis and treatment of von Willebrand disease

Clinical and laboratory variability in a cohort of patients diagnosed with type 1 VWD in the United States

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