Features Partner Sites Information LinkXpress hp
Sign In
Advertise with Us
LGC Clinical Diagnostics

Siemens Healthineers - Laboratory Diagnostics

Provides advanced laboratory diagnostics solutions for the medical industry read more Featured Products: More products

Download Mobile App




Automated Methods Evaluated for Von Willebrand Factor Activity

By LabMedica International staff writers
Posted on 12 Jun 2014
Von Willebrand factor (VWF) assays have an important role in the diagnostic evaluation, and treatment monitoring, of von Willebrand disease (VWD), which is one of the most common coagulopathies or bleeding disorders.

The laboratory evaluation for VWD requires an assessment of plasma VWF activity, which is commonly done using an aggregometer to assess VWF ristocetin cofactor activity which is a quantitative method that uses the antibiotic ristocetin to induce plasma VWF binding to the VWF receptor on target platelets and platelet agglutination.

Scientists at the McMaster University (Hamilton, ON, Canada) evaluated 262 samples from 217 patients that included 188 samples from 153 females and 73 samples from 63 males. There were 197 samples from adults (ages 18 to 84) and 64 from children (ages 0 to 17 years), and 67 samples were from 34 patients with previously diagnosed VWD. After validating that the assay could be performed on an instrument from a different manufacturer, they compared VWF activity assay (VWF:Ac) to VWF ristocetin cofactor activity (VWF:RCo) findings, including ratios of activity/antigen.

Plasma was tested by the VWF:Ac on an STA-R Evolution (Diagnostica Stago; Parsippany, NJ, USA) and using the Innovance assay on a Sysmex CS2000i instrument (Siemens; Erlangen, Germany). VWF:RCo was performed by aggregometry on a Helena AggRAM instrument (Helena Laboratories, Beaumont, TX, USA). There was excellent correlation between VWF:Ac results run at two different sites on two different instruments. VWF:Ac had greater precision and sensitivity to low levels of VWF than the VWF:RCo method.

Although there was good correlation between VWF:Ac and VWF:RCo results among healthy controls and patient subjects, VWF:Ac results were undetectable and/or significantly lower than VWF:RCo among patients who had types 2A, 2B, or 2M VWD. Additionally, a higher proportion of patient samples were classified as showing qualitative defects using the VWF:Ac compared with VWF:RCo method.

The authors concluded that the Innovance VWF:Ac method is an acceptable, automated alternative to the VWF:RCo method for assessment of VWF binding to the platelet receptor glycoprotein GPIbα that is sensitive to both quantitative and qualitative defects of VWF. Laboratories and clinicians need to be aware that some patients with VWD have much lower levels of VWF measured by the VWF:Ac assay than by VWF:RCo. The study was published on April 18, 2014, in the International Journal of Laboratory Hematology.

Related Links:

McMaster University 
Diagnostica Stago
Siemens Healthcare




Gold Member
Fully Automated Cell Density/Viability Analyzer
BioProfile FAST CDV
Verification Panels for Assay Development & QC
Seroconversion Panels
New
Total 25-Hydroxyvitamin D₂ & D₃ Assay
25-OH-VD Reagent Kit
New
Biological Indicator Vials
BI-O.K.
Read the full article by registering today, it's FREE! It's Free!
Register now for FREE to LabMedica.com and get access to news and events that shape the world of Clinical Laboratory Medicine.
  • Free digital version edition of LabMedica International sent by email on regular basis
  • Free print version of LabMedica International magazine (available only outside USA and Canada).
  • Free and unlimited access to back issues of LabMedica International in digital format
  • Free LabMedica International Newsletter sent every week containing the latest news
  • Free breaking news sent via email
  • Free access to Events Calendar
  • Free access to LinkXpress new product services
  • REGISTRATION IS FREE AND EASY!
Click here to Register








Channels

Clinical Chemistry

view channel
Image: The tiny clay-based materials can be customized for a range of medical applications (Photo courtesy of Angira Roy and Sam O’Keefe)

‘Brilliantly Luminous’ Nanoscale Chemical Tool to Improve Disease Detection

Thousands of commercially available glowing molecules known as fluorophores are commonly used in medical imaging, disease detection, biomarker tagging, and chemical analysis. They are also integral in... Read more

Immunology

view channel
Image: The cancer stem cell test can accurately choose more effective treatments (Photo courtesy of University of Cincinnati)

Stem Cell Test Predicts Treatment Outcome for Patients with Platinum-Resistant Ovarian Cancer

Epithelial ovarian cancer frequently responds to chemotherapy initially, but eventually, the tumor develops resistance to the therapy, leading to regrowth. This resistance is partially due to the activation... Read more

Microbiology

view channel
Image: The lab-in-tube assay could improve TB diagnoses in rural or resource-limited areas (Photo courtesy of Kenny Lass/Tulane University)

Handheld Device Delivers Low-Cost TB Results in Less Than One Hour

Tuberculosis (TB) remains the deadliest infectious disease globally, affecting an estimated 10 million people annually. In 2021, about 4.2 million TB cases went undiagnosed or unreported, mainly due to... Read more

Pathology

view channel
Image: The ready-to-use DUB enzyme assay kits accelerate routine DUB activity assays without compromising data quality (Photo courtesy of Adobe Stock)

Sensitive and Specific DUB Enzyme Assay Kits Require Minimal Setup Without Substrate Preparation

Ubiquitination and deubiquitination are two important physiological processes in the ubiquitin-proteasome system, responsible for protein degradation in cells. Deubiquitinating (DUB) enzymes contain around... Read more

Technology

view channel
Image: The HIV-1 self-testing chip will be capable of selectively detecting HIV in whole blood samples (Photo courtesy of Shutterstock)

Disposable Microchip Technology Could Selectively Detect HIV in Whole Blood Samples

As of the end of 2023, approximately 40 million people globally were living with HIV, and around 630,000 individuals died from AIDS-related illnesses that same year. Despite a substantial decline in deaths... Read more

Industry

view channel
Image: The collaboration aims to leverage Oxford Nanopore\'s sequencing platform and Cepheid\'s GeneXpert system to advance the field of sequencing for infectious diseases (Photo courtesy of Cepheid)

Cepheid and Oxford Nanopore Technologies Partner on Advancing Automated Sequencing-Based Solutions

Cepheid (Sunnyvale, CA, USA), a leading molecular diagnostics company, and Oxford Nanopore Technologies (Oxford, UK), the company behind a new generation of sequencing-based molecular analysis technologies,... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.