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Thromb Haemost 1998; 79(04): 872-875
DOI: 10.1055/s-0037-1615080
Scientific and Standardization Committee Communication
Schattauer GmbH

A Detailed Comparison of the Performance of the Standard versus the Nijmegen Modification of the Bethesda Assay in Detecting Factor VIII:C Inhibitors in the Haemophilia A Population of Canada

Alan R. Giles
1   From the AHCDC Factor VIII Inhibitor Reference Laboratory Kingston General Hospital, Kingston, Ontario, Canada
2   From the Association of Hemophilia Centre Directors of Canada (AHCDC), Toronto, ON, Canada
,
Bert Verbruggen
3   From the Central Laboratory for Hematology of Academic Hospital St. Radboud, Nijmegen, The Netherlands
,
Georges E. Rivard
2   From the Association of Hemophilia Centre Directors of Canada (AHCDC), Toronto, ON, Canada
,
Jerome Teitel
2   From the Association of Hemophilia Centre Directors of Canada (AHCDC), Toronto, ON, Canada
,
Irwin Walker
2   From the Association of Hemophilia Centre Directors of Canada (AHCDC), Toronto, ON, Canada
,
Association of Hemophilia Centre Directors of Canada, Factor VIII/IX Subcommittee of Scientific and Standardization Committee of International Society on Thrombosis and Haemostasis › Author Affiliations
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Publication History





Publication Date:
07 December 2017 (online)

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Summary

The Bethesda assay is widely used to monitor the development and progress of Factor VIII:C inhibitors. Factor VIII stability in the substrate plasma (normal pool) is compromised by pH shift and reduction in protein concentration. Preliminary study, by Verbruggen and colleagues (8), suggested a reduction in spuriously positive assay results may result from buffering the normal pool plasma substrate with imidazole to pH 7.4 and substituting Factor VIII deficient plasma for imidazole buffer in the control incubation mix. These laboratory findings have now been confirmed by the performance of both the standard and the modified Bethesda assays in parallel on 877 patient samples screened during the Factor VIII:C Inhibitor Surveillance Program instituted following the conversion of all Canadian haemophilia A patients to recombinant Factor VIII. Although this study does not address the question of the clinical significance of spurious positive assays, these laboratory findings do support the conclusions of Verbruggen and the modified assay has recently been endorsed by the Factor VIII/IX Subcommittee of the SSC.

* Association of Hemophilia Clinic Directors of Canada (AHCDC): Gerry Growe, Man-Chiu Poon, John Wu, Robert Card, Kaiser Ali, Sara Israels, Morel Rubinger, Jordan Herst, Kulwant Gill, Martin Inwood, Patricia J. McCusker, Irwin Walker, Mohan Pai, Bernadette Garvey, Jerome Teitel, Victor Blanchette, Alan Giles, David Lillicrap, Mariana Silva, Jeanne Drouin, Koon-Hung Luke, Mason Bond, Michele David, Georges Rivard, Jean St-Louis, Mariette Lepine-Martin, Christine Demers, Francois Jobin, Marie- Frances Scully, Sean Dolan, Sheldon Rubin, Dorothy Barnard, Sue Robinson, Elizabeth Ross, Lawrence Jardine


 

  • References

  • 1 Kasper CK. Complications of Hemophilia A Treatment: Factor VIII Inhibitors. Ann NY Acad Sci 1991; 614: 97-105.
    CrossrefPubMedGoogle Scholar
  • 2 McMillan CW, Shapiro SS, Whitehurst D, Hoyer LW, Rao AV, Lazerson J. The Natural History of Factor VIII:C Inhibitors in Patients With Hemophilia A: A National Cooperative Study. II. Observations on the initial Development of Factor VIII:C Inhibitors. Blood 1988; 71: 344-8.
    PubMedGoogle Scholar
  • 3 Ehrenforth S, Kreuz W, Scharrer I, Linde R, Funk M, Gungor T, Krackhardt B, Kornhuber B. Incidence of Development of Factor VIII and Factor IX Inhibitors in Haemophiliacs. Lancet 1992; 339: 594-8.
    CrossrefPubMedGoogle Scholar
  • 4 Rizza CR, Matthews JM. Effect of Frequent Factor VIII Replacement on the Level of Factor VIII Antibodies in Haemophiliacs. Brit J Haematol 1982; 52: 13-24.
    CrossrefPubMedGoogle Scholar
  • 5 Coots MC, Glueck HI. The Persistence and Heterogeneity of Factor VIII:C Inhibitors as Demonstrated by Preparative Isofocusing. Amer J Hematol 1990; 35: 73-9.
    CrossrefPubMedGoogle Scholar
  • 6 Kasper CK, Aledort LM, Counts RB, Edson JR, Fratantoni J, Green D, Hampton JW, Hilgartner MW, Lazerson J, Levine PH, McMillan CW, Pool JG, Shapiro SS, Shulman NR, Van Eys J. A More Uniform Measurement of Factor VIII Inhibitors. Thromb Diath Haemorrh 1975; 34: 869-72.
    PubMedGoogle Scholar
  • 7 Lusher JM, Arkin S, Abildgaard CF, Schwartz RS. Recombinant Factor VIII for the Treatment of Previously Untreated Patients with Hemophilia A. New Engl J Med 1993; 328: 453-9.
    CrossrefPubMedGoogle Scholar
  • 8 Verbruggen B, Novakova I, Wessels H. et al. The Nijmegen Modification of the Bethesda Assay for Factor VIII:C Inhibitors: Improved Specificity and Reliability. Thromb Haemost 1995; 73: 247-51.
    Article in Thieme ConnectPubMedGoogle Scholar
  • 9 Proctor RR, Rapaport SI. The Partial Thromboplastin Time with Kaolin; a Simple Screening Test for first-stage Plasma Clotting Factor Deficiencies. Amer J Clin Path 1961; 36: 212-9.
    PubMedGoogle Scholar
  • 10 Giles AR, Rivard GE, Teitel J, Walker I. and the Association of Hemophilia Centre Directors of Canada (AHCDC). The Prevalence of Factor VIII Inhibitor Development in the Canadian hemophilia Population Following the Wide-scale Introduction of High Purity Factor VIII Replacement Therapy. Haemophilia 1996; 2 (Suppl. 01) 89 (Abstract).
    PubMedGoogle Scholar
  • 11 Giles AR, Rivard GE, Teitel J, Walker I. and the Association of Hemophilia Centre Directors of Canada (AHCDC).. A Multicenter Study Comparing Assay Performance of “In House” Methods of Measuring F. VIII Inhibitors Versus Standardized Methodology (Manuscript in Preparation).
    PubMedGoogle Scholar