Assay Aids Diagnosis and Monitoring of von Willebrand Disease

A new, fully automated assay aids in the diagnosis and monitoring of von Willebrand disease (VWD).

HemosIL VWF:RCo assay detects quantitative and qualitative von Willebrand Factor (vWF) defects (VWD Type 1, 2, and 3). It is based on the principle that a recombinant fragment of the platelet receptor, glycoprotein-Ib alpha contains the vWF-binding site. The VWF: RCo reagent consists of a latex particle, coated with glycoprotein-Ib alpha, through a highly specific monoclonal antibody. If vWF is present in the sample, it will bind to the glycoprotein-Ib alpha fragment, in the presence of ristocetin. The degree of agglutination is directly proportional to the activity of vWF in the sample, and is determined by measuring the decrease of transmitted light caused by the aggregates.

The assay represents an innovative approach to VWD testing. Demonstrating excellent agreement with existing ristocetin-platelet-based tests, the HemosIL VWF: RCo assay eliminates platelet-associated variability. Additionally, variability associated with human interpretation, common with manual testing methods, is eliminated. Because the assay is automated, liquid, and ready-to-use, results are available in minutes and on-demand, 24/7.
Instrumentation Laboratory (IL; Bedford, MA, USA) announced the release of the HemosIL VWF: RCo assay as a European CE in vitro diagnostic (IVD) Mark product under the European Directive on in vitro diagnostic medical devices. The assay will be commercialized in Europe and other international regions. The automated VWF: RCo assay is for use on the ACL TOP family of hemostasis testing systems.

VWD is the most common inherited blood disorder, occurring in approximately 1% of the general population. It disrupts the blood's ability to clot properly. Unlike hemophilia, it affects both genders and is caused by a quantitative defect (i.e., vWF level is abnormally low) or a qualitative defect (i.e., vWF has abnormal physical characteristics) of the vWF. A large protein involved in primary hemostasis, vWF helps platelets stick to damaged vessel walls and carries the clotting protein, Factor VIII, in the blood. For those with a moderate-to-severe form of the disease, proper diagnosis and treatment is essential.

"This important new addition to our portfolio of vWF assays will help ensure early diagnosis and proper treatment for patients," said Remo Tazzi, director, hemostasis marketing at IL. "By simplifying and automating a complex procedure, the HemosIL VWF: RCo assay marks a significant improvement in not only the turnaround time for results, but also in accuracy and precision. It is a perfect example of our commitment to providing specialized solutions for disease-state management."

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