Related Experiment Video
Updated: Jul 3, 2026
Investigating von Willebrand Factor Pathophysiology Using a Flow Chamber Model of von Willebrand Factor-platelet String Formation
Published on: August 14, 2017
Second international collaborative study evaluating performance characteristics of methods measuring the von
A Tripodi1, F Peyvandi, V Chantarangkul
1Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Department of Internal Medicine and Medical Specialties, University and IRCCS Maggiore Hospital, Milan, Italy. armando.tripodi@unimi.it
Background:
Over the last 4 years ADAMTS-13 measurement underwent dramatic progress with newer and simpler methods.
Aims:
Blind evaluation of newer methods for their performance characteristics.
Design:
The literature was searched for new methods and the authors invited to join the evaluation. Participants were provided with a set of 60 coded frozen plasmas that were prepared centrally by dilutions of one ADAMTS-13-deficient plasma (arbitrarily set at 0%) into one normal-pooled plasma (set at 100%). There were six different test plasmas ranging from 100% to 0%. Each plasma was tested 'blind' 10 times by each method and results expressed as percentage vs. the local and the common standard provided by the organizer.
Results:
There were eight functional and three antigen assays. Linearity of observed-vs.-expected ADAMTS-13 levels assessed as r2 ranged from 0.931 to 0.998. Between-run reproducibility expressed as the (mean) CV for repeated measurements was below 10% for three methods, 10-15% for five methods and up to 20% for the remaining three. F-values (analysis of variance) calculated to assess the capacity to distinguish between ADAMTS-13 levels (the higher the F-value, the better the capacity) ranged from 3965 to 137. Between-method variability (CV) amounted to 24.8% when calculated vs. the local and to 20.5% when calculated vs. the common standard. Comparative analysis showed that functional assays employing modified von Willebrand factor peptides as substrate for ADAMTS-13 offer the best performance characteristics.
Conclusions:
New assays for ADAMTS-13 have the potential to make the investigation/management of patients with thrombotic microangiopathies much easier than in the past.
