Von Willebrand Disease (VWD)
Part 3: VWF Activity Assay
A New von Willebrand Factor Activity Assay and Testing Algorithm
Sample Categorization
June 2011
We then categorized samples into normal, type 1, type 2 VWD, severe type 1 vs 2M VWD and acquired VWF abnormality (AVWA in abbreviation). This categorization is for method comparison. Most of them are self-explanatory. The severe type 1 versus 2M VWD categorize samples whose VWF ristocetin cofactor activities were below lower detection limit and their VWF multimer analysis showed no significant loss of high molecular weight multimers. Therefore, they can not be confidently distinguished between a severe type 1 or 2M von Willebrand disease. Acquired VWF abnormality (AVWA) categorizes samples with normal VWF antigen and ristocetin cofactor activity but have very subtle losses of highest molecular weight multimers.
Sample Categorization |
Jump to section:
- Introduction
- Objectives
- History of VWF Ristocetin Cofactor Activity (VWF:RCo) Assay
- Problems with VWF:RCo Assay
- Summary of External Quality Assessment of VWF:RCo
- von Willebrand Disease(VWD) Diagnostic Error Rates Due to Erroneous VWF:RCo Results5
- VWF:RCo/Ag Ratio is Insensitive for Aquired von Willebrand Abnormalities (AVWA)
- VWF:RCo is Inadequate for Detecting AVW Abnormality
- The New Automated VWF Activity by Latex-Immunoturbidity Assay (VWF:Lx)
- VWF Activity Assay by an A1 Domain Conformation-Sensitive Antibody6
- Performance Characteristics of VWF:Lx
- VWF:Lx and VWF:RCo Method Comparison
- VWF:Lx and VWF:RCo Bias Analysis
- Sample Categorization
- Comparison of VWF:Lx/Ag and VWF:RCo/Ag Ratios
- VWF:Lx and VWF:RCo Errors
- Severe Type 1 vs 2M7
- VWF:Lx and RCo Errors
- VWF:Lx/Ag is Sensitive to AVWA with Subtle Loss of Highest HMWM
- ROC Analysis of VWF:Lx/Ag and VWF:RCo/Ag for Detecting AVWA with Loss of HMWMs
- VWF:Lx/Ag vs VWF:RCo/Ag Ratios
- VWF Laboratory Testing Strategy
- Sensitivity and Specificity of the Screening Panel
- von Willebrand Disease Profile
- von Willebrand Disease Profile
- von Willebrand Disease Profile
- von Willebrand Disease Profile
- Limitations of VWF:Lx
- Summary
- References
- Questions?
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