Corewell Health Laboratory (Grand Rapids) Coagulation laboratory is pleased to announce a change to our von Willebrand factor (VWF) activity test. The historical test von Willebrand ristocetin cofactor (LAB335) will be retired and replaced by von Willebrand factor activity (VWF activity, LAB1230904) on January 17, 2023.
The new VWF activity test uses the Innovance assay to test the binding of von Willebrand factor to glycoprotein 1b (GP1b), the major VWF receptor protein on platelets. This assay has been shown to provide excellent reproducibility over the full range of clinical measurements and diagnostic accuracy when correlated with the previous ristocetin cofactor assay. It can be used in the same way to determine a VWF activity: VWF antigen ratio for clinical decision making regarding possible type 1 vs. type 2 von Willebrand disease.
The new VWF activity GP1b test does not have false low results with genetic polymorphisms that were present with ristocetin testing. Individuals with blood group type O can have VWF testing results with all VWF assays that are significantly lower than individuals with non-O blood group type. Manufacturer details, including additional reference ranges, may be available upon request.
For additional request, questions, inquiries, or interface codes please use the contact us link above.
Discontinued: von Willebrand Ristocetin Cofactor [LAB335]