Register Login

Ristocetin Cofactor

Laura Lum, Seattle Children’s Hospital, asks, What is the ristocetin cofactor assay for, how is it performed, and can it be done on an STA Compact?

Hi, Laura, the ristocetin cofactor assay is a test for von Willebrand factor (VWF) activity. Low VWF is the cause of von Willebrand disease (VWD). The assay began as platelet aggregometry in which patient platelet-poor plasma is mixed with preserved reagent platelets such as are provided in Chrono-Log Corp Ristocetin Cofactor Assay Kit. Then ristocetin reagent is added and aggregation is recorded. The degree of tracing deflection estimates the concentration of VWF.

Siemens Healthcare Diagnostics, Inc offers an automated form of the assay, their BC von Willebrand reagent, designed to work on Siemens’ instruments. Several US lab operators have successfully adapted Siemens reagent to Stago equipment, and you can obtain assistance from you account manager or the technical support folks at Stago if you would like to adapt the assay to your instrument. Geo.

Comments (3)
Bleeding Disorders
Nov 26, 2019 11:30am

Is there anyone out there
Is there anyone out there that uses Siemens Ristocetin in their STARMAX or EVOLUTION? Please tell me what QC you are using and what dilution you use to configure your STAGO instrument for patient and QC. Please if you can email me [email protected] or call me at 617-355-5850
Rodel Rosales MT-ASCP, Technical Specialist at Boston Children’s Core Lab

Mar 7, 2012 2:22pm

Hi Laura! We use the IL (HemosIL) von Willebrand Factor Acti
Hi Laura! We use the IL (HemosIL) von Willebrand Factor Activity assay on our STAGO STAR evolution. This assay replaced our old ristocetin activity. We have had a lot of success with this assay in picking up different types of von Willebrand Disease.
Hope this helps!

Feb 9, 2012 8:44pm

Hi Laura and Geo!
I would like to know, other than Siemens

Hi Laura and Geo!
I would like to know, other than Siemens BC von Willebrand reagent, is there any other company offers this assay (automated)?

Joyce, I believe Siemens provides the only automated ristocetin cofactor assay, though it can be set up on other instruments besides their BCS. Geo.

Leave a Reply