Von Willebrand Disease (VWD)
Part 3: VWF Activity Assay
A New von Willebrand Factor Activity Assay and Testing Algorithm
Performance Characteristics of VWF:Lx
June 2011
The key laboratory characteristics of the new VWF activity assay, are as follows:
The lower detection limit is 3 U/dL. Linearity is between 3 to 350 U/dL. The inter- and intra-precisions are all around 5%. Citrated plasma samples are stable for 8 hours at room temperature. This assay is fully automated on our TOP coagulation analyzers which could significantly improve test turn-around time.
Performance Characteristics of VWF:Lx |
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?


