RSS-Feed abonnieren
DOI: 10.1055/s-2006-947863
Laboratory Tests for Measurement of von Willebrand Factor Show Poor Agreement among Different Centers: Results from the United Kingdom National External Quality Assessment Scheme for Blood Coagulation
Publikationsverlauf
Publikationsdatum:
24. Juli 2006 (online)
![](https://www.thieme-connect.de/media/sth/200605/lookinside/thumbnails/10.1055-s-2006-947863-1.jpg)
ABSTRACT
In recognition of the importance of von Willebrand factor (vWF) testing in the diagnosis of von Willebrand disease (vWD), the United Kingdom National External Quality Assessment Scheme for Blood Coagulation regularly distributes samples for determination of vWF:antigen (vWF:Ag). Data from 10 separate surveys performed between 2001 and 2005 are reviewed. These include results from ~200 different centers, of which 55% are within the United Kingdom and the remainder are from other countries. During the period of the surveys, the use of immunoelectrophoresis for determination of vWF:Ag practically disappeared and was largely replaced by latex agglutination assays. The coefficient of variation (CV) of results in different centers was ~15 to 20% for most vWF:Ag techniques, with CVs of ~7% for a fluorescence-based assay. Several different techniques were used for determination of vWF ristocetin cofactor activity (vWF:RCo), all of which were associated with poor agreement among centers as indicated by CVs of 40 to 50%. Several centers calculated the ratio of vWF:Ag/vWF:RCo but with variable success. Ratios compatible with either type 1 or type 2 vWD were obtained on samples from subjects with type 1 vWD, as well as on samples from subjects with genetically confirmed type 2 vWD. Overall, our data show that laboratory testing for vWD remains problematic. It remains to be seen whether newer techniques will offer consistently improved precision.
KEYWORDS
von Willebrand factor:antigen (vWF:Ag) - von Willebrand factor:ristocetin cofactor activity (vWF:RCo) - laboratory assays - von Willebrand disease (vWD)
REFERENCES
- 1 Laffan M, Brown S A, Collins P W et al.. The diagnosis of von Willebrand disease: a guidance from the UK Haemophilia Centre Doctors' Organisation. Haemophilia. 2004; 10 199-217
- 2 Sadler J E, Mannucci P M, Berntorp E et al.. Impact, diagnosis and treatment of von Willebrand disease. Thromb Haemost. 2000; 84 160-174
- 3 Favaloro E. Von Willebrand factor: collagen binding (activity) assay in the diagnosis of von Willebrand disease: a 15 year journey. Semin Thromb Hemost. 2002; 28 191-202
- 4 Pasi K J, Collins P W, Keeling D M et al.. Management of von Willebrand's disease: a guideline from the UK Haemophilia Centre Doctors' Organisation. Haemophilia. 2004; 10 218-231
- 5 Allen S, Abuzenadah A M, Blagg J L et al.. Two novel 2N von Willebrand disease-causing mutations that result in defective factor VIII binding multimerization and secretion of von Willebrand factor. Blood. 2000; 95 2000-2007
- 6 Sadler J E. Von Willebrand disease type 1: a diagnosis in search of a disease. Blood. 2003; 101 2089-2093
- 7 Castaman G, Federici A B, Rodeghiero F, Mannucci P M. Von Willebrand's disease in the year 2003: towards the complete identification of gene defects for correct diagnosis and treatment. Haematologica. 2003; 88 94-108
- 8 Jennings I, Kitchen S, Woods T AL, Preston F E. Laboratory performance of haemophilia centres in developing countries. A three year experience of the WFH EQA scheme. Haemophilia. 1998; 4 739-746
- 9 Murdock P J, Woodhams B J, Matthews K B, Pasi K J, Goodall A H. Von Willebrand factor activity detected in a monoclonal antibody-based ELISA: an alternative to the ristocetin cofactor platelet agglutination assay for diagnostic use. Thromb Haemost. 1997; 78 1272-1277
- 10 Preston F E. Assays for von Willebrand factor functional activity: a UK National External Quality Assessment Scheme survey. Thromb Haemost. 1998; 80 863
- 11 Federici A B, Conciani M T, Forza I, Cozzi G. Ristocetin cofactor and collagen binding activities normalised to antigen levels for a rapid diagnosis of type 2 VWD. Thromb Haemost. 2000; 84 1127-1128
- 12 Nitu-Whalley I C, Riddell A, Lee C A et al.. Identification of type 2 von Willebrand disease in previously diagnosed type 1 patients: a reappraisal using phenotypes, genotypes and molecular modelling. Thromb Haemost. 2000; 84 998-1004
- 13 Vanhoorelbeke K, Cauwenberghs N, Vauterin S, Schlammadinger A, Mazurier C, Deckmyn H. A reliable and reproducible ELISA method to measure ristocetin cofactor activity of von Willebrand Factor. Thromb Haemost. 2000; 83 107-113
- 14 Creagmile S D, Geighton R I, Ewan B EA, Forto R P, Pritchard D J, Wilson P A. A von Willebrand factor ELISA with improved detection of type 2 patient samples. Thromb Haemost. 1999; (suppl; abst 614)
- 15 Favaloro E, Bonar R, Sioufi J et al.. Laboratory diagnosis of von Willebrand disorder: current practice in the Southern Hemisphere. Am J Clin Pathol. 2003; 119 882-893
- 16 Favaloro E J, Bonar R, Kershaw G et al.. Royal College of Pathologists of Australasia Quality Assurance Program in Haematology. Laboratory diagnosis of von Willebrand disorder: use of multiple functional assays reduces diagnostic error rates. Lab Hematol. 2005; 11 91-97
- 17 Federici A B, Mazurier C, Berntop E et al.. Biologic response to desmopressin in patients with severe type 1 and type 2 VWD: results of a multicentre European study. Blood. 2004; 103 2032-2038
Steve KitchenPh.D.
United Kingdom National External Quality Assessment Scheme (NEQAS) for Blood Coagulation, Rutledge Mews
3 Southbourne Road, Sheffield, [postal code] United Kingdom
eMail: Steve.Kitchen@sth.nhs.uk