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Thromb Haemost 2002; 88(01): 56-59
DOI: 10.1055/s-0037-1613154
Review Article
Schattauer GmbH

Evaluation of Two Automated Methods for Measurement of the Ristocetin Cofactor Activity of von Willebrand Factor

Connie H. Miller
1   Hematologic Diseases Branch, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
,
S. Jean Platt
1   Hematologic Diseases Branch, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
,
Christine Daniele
2   Diagnostica Stago Inc., Parsippany, New Jersey, USA
,
Daniel Kaczor
2   Diagnostica Stago Inc., Parsippany, New Jersey, USA
› Author Affiliations
Further Information

Publication History

Received 29 November 2001

Accepted after revision 21 March 2002

Publication Date:
09 December 2017 (online)

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Summary

We have evaluated two automated methods for measuring ristocetin cofactor activity (VWF:RCo) on an automated coagulation analyzer (STAR®, Diagnostica Stago Inc., Parsippany, NJ). A modification of the BC von Willebrand Reagent method (Dade Behring Inc., Newark, Delaware) was compared with a standard method using a platelet aggregometer, and an in-house automated method was developed using commercially available components. The STAR® measures the change in optical density (OD) caused by agglutination of platelets. Change in OD was linear for plasma dilutions between .25 and .04 U/mL. Coefficient of variation compared favorably with that of the standard method. In 123 normal women, the correlation coefficient (r) = .905. In menorrhagia cases, r = .901. In 20 VWD patients, r = .93. The CDC in-house method was compared to the BC Reagent method in 79 additional menorrhagia cases, with r = .94. The automated methods produced results equivalent or superior to those of traditional methods of measuring VWF:RCo.

Keywords

von Willebrand factor - ristocetin cofactor - methods
 

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