Advertisement

Research in Clinic and Laboratory

, Volume 20, Issue 2, pp 155–165 | Cite as

Standardization of assays of factor VIII and factor IX

  • Trevor W. Barrowcliffe
From Meetings 2nd International Symposium On Standardization And Quality Control Of Coagulation Tests: Implications For The Clinical Laboratory
  • 84 Downloads

Summary

The development of international standards over the last 15–20 years has led to improved interlaboratory agreement on assays of factor VIII and factor IX. In the most recent international collaborative study, the coefficient of variation for one-stage assays (26 laboratories) was 5.6%. However, in quality assurance surveys, carried out in the UK and USA, agreement between laboratories is much less good, with coefficients of variation ranging from 30% to over 50%. Improvements in agreement between clinical laboratories could be obtained by increasing the amount of testing on each sample, especially the number of dilutions, and reducing the number of reagent systems used. A large number of laboratories now use immunodepleted plasmas instead of congenitally deficient plasmas as substrates for one-stage assays. These plasmas may give satisfactory assays, but many of them have not been thoroughly evaluated in comparison with congenitally deficient plasma. In assessment of potency of very high purity (VHP) factor VIII concentrates, some immunodepleted plasmas were found to give lower potencies than hemophilic plasma. This is partly due to the fact that VHP concentrates contain little or no von Willebrand factor (vWF), and most immunodepleted plasmas are also deficient in vWF. In recent collaborative studies, assays of VHP factor VIII concentrate were much more variable, both within and between laboratories, than assays of intermediate purity concentrates. Standardization of these new products will require careful attention to methodological detail.

Key-words

Assays Factor VIII Factor IX Standards 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Bangham D. R., Biggs R., Brozovic M., Denson K. W. E., Skegg J. L.: A biological standard for measurement of blood coagulation factor VIII activity — Bull. Wld Hlth Org.45, 337, 1971.Google Scholar
  2. 2.
    Barrowcliffe T. W.: Comparisons of 1-stage and 2-stage assays of factor VIII:C — Scand. J. Haematol.33, 39, 1984.Google Scholar
  3. 3.
    Barrowcliffe T. W.: The 1-stage versus the 2-stage factor VIII assay. In:Triplett D. A. (Ed.): Advances in Coagulation Testing: Interpretation and Application. College of American Pathologists Press, Skokie, IL., 1985; chapt. 5.Google Scholar
  4. 4.
    Barrowcliffe T. W., Curtis A. D.: An international collaborative study of factors II, VII, IX and X — NIBSC unpublished report, 1986.Google Scholar
  5. 5.
    Barrowcliffe T. W., Curtis A. D., Thomas D. P.: Standardisation of factor VIII. IV. Establishment of the 3rd international standard for factor VIII:C concentrate — Thrombos. Haemostas.50, 697, 1983.Google Scholar
  6. 6.
    Barrowcliffe T. W., Dawson N. J., Kemball-Cook G.: Activated factor VIII in concentrates prepared by monoclonal antibody and recombinant technology — Thrombos. Haemostas.60, 198, 1989.Google Scholar
  7. 7.
    Barrowcliffe T. W., Edwards S. J., Kemball-Cook G., Thomas D. P.: Factor VIII degradation products in heated concentrates — Lanceti, 1448, 1986. (Letter).CrossRefGoogle Scholar
  8. 8.
    Barrowcliffe T. W., Heath A. B.: Establishment of the 4th international standard for factor VIII concentrate — NIBSC unpublished report, 1989.Google Scholar
  9. 9.
    Barrowcliffe T. W., Kemball-Cook G., Heath A. B.: A collaborative study of intermediate and very high purity factor VIII concentrates — NIBSC unpublished report, 1989.Google Scholar
  10. 10.
    Barrowcliffe T. W., Kirkwood T. B. L.: An international collaborative assay of factor VIII clotting activity — Thrombos. Haemostas.40, 260, 1978.Google Scholar
  11. 11.
    Barrowcliffe T. W., Kirkwood T. B. L.: Standardisation of factor VIII. I. Calibration of British standards for factor VIII clotting activity — Brit. J. Haematol.46, 471, 1980.CrossRefGoogle Scholar
  12. 12.
    Barrowcliffe T. W., Tydeman M. S., Kirkwood T. B. L., Thomas D. P.: Standardization of factor VIII. III. Establishment of a stable reference plasma for factor VIII-related activities — Thrombos. Haemostas.50, 690, 1983.Google Scholar
  13. 13.
    Blombäck M.: Synthetic chromogenic substrate assay for factor VIII. In:Triplett D. A. (Ed.): Advances in Coagulation Testing: Interpretation and Application. College of American Pathologists Press, Skokie, IL, 1985; chapt. 3.Google Scholar
  14. 14.
    Bovill E. G., Triplett D. A.: Review of the College of American Pathologists proficiency survey results for factor VIII:C assays 1983 through 1984. In:Triplett D. A. (Ed.): Advances in Coagulation Testing: Interpretation and Application. College of American Pathologists Press, Skokie, IL, 1985; chapt. 9.Google Scholar
  15. 15.
    Brozovic M., Kirkwood T. B. L., Robertson I.: Study of a proposed international standard for blood coagulation factor IX — Thrombos. Haemostas.35, 222, 1976.Google Scholar
  16. 16.
    Dawson N. J., Kemball-Cook G., Barrowcliffe T. W.: Assay discrepancies with highly purified factor VIII concentrates — Haemostasis19, 131, 1989.PubMedGoogle Scholar
  17. 17.
    Heldebrant C., Kleszynski R., Short M., Aronson D., Brown L., Jacoby G., Lee M., Thomas D., Barrowcliffe T., Howell I., Johnson R. C.: Assay of AHF concentrates and standards: failure to eliminate variability with a monographed assay — Thrombos. Res.30, 337, 1983.CrossRefGoogle Scholar
  18. 18.
    Hubbard A. R., Curtis A. D., Barrowcliffe T. W., Edwards S. J., Jennings C. A., Kemball-Cook G.: Assay of factor VIII concentrates: comparison of chromogenic and 2-stage clotting assays — Thrombos. Res.44, 887, 1986.CrossRefGoogle Scholar
  19. 19.
    Kirkwood T. B. L., Barrowcliffe T. W.: Discrepancy between 1-stage and 2-stage assay of factor VIII:C — Brit. J. Haematol.40, 333, 1978.CrossRefGoogle Scholar
  20. 20.
    Koedam J. A., Hamer R. J., Beeser-Visser N. H., Jap E., San T., Schippers K., Sixma J. J.: The interaction between factor VIII and von Willebrand factor — Thrombos. Haemostas.58, 538, 1987. (Abstract).Google Scholar
  21. 21.
    Lee M. L., Magalang E. A., Kingdon H. S.: An effect of predilution on potency assays of factor VIII concentrates — Thrombos. Res.30, 511, 1983.CrossRefGoogle Scholar
  22. 22.
    Middleton S. A.: Evaluation of an immunodepleted factor IX-deficient plasma — Speywood Laboratories unpublished report, 1986.Google Scholar
  23. 23.
    Mikaelsson M., Oswaldsson U.: Standardization of VIII:C assays: a manufacturer’s view — Scand. J. Haematol.33, 79, 1984.Google Scholar
  24. 24.
    Over J.: Quality control of the 1-stage factor VIII (VIII:C) assay in the coagulation laboratory — Scand. J. Haematol.33, 89, 1984.Google Scholar
  25. 25.
    Prowse C.: Evaluation of an immunodepleted factor IX-deficient plasma — SNBTS unpublished report, 1987.Google Scholar
  26. 26.
    Rosén S., Anderson M., Blombäck M., Hagglund U., Larrieu M. J., Wolf M., Boyer C., Rothschild C., Nilsson J. M., Sjorin E., Vinazzer H.: Clinical application of a chromogenic substrate method for determination of factor VIII activity — Thrombos. Haemostas.54, 818, 1985.Google Scholar
  27. 27.
    Standardization of factors II, VII, IX and X in plasma and concentrates — Report of the ICTH Subcommittee on factors VIII and IX, Brussels, 1987 — Thrombos. Haemostas.59, 334, 1988.Google Scholar
  28. 28.
    Wld Hlth Org. techn. Rep. Ser.463, 14, 1971.Google Scholar
  29. 29.
    Wld Hlth Org. techn. Rep. Ser.610, 13, 1977.Google Scholar
  30. 30.
    Wld Hlth Org. techn. Rep. Ser.771, 23, 1988.Google Scholar

Copyright information

© Casa Editrice «Il Ponte» 1990

Authors and Affiliations

  • Trevor W. Barrowcliffe
    • 1
  1. 1.National Institute for Biological Standards and ControlBlanche Lane, South Mimms Potters BarHertfordshireGreat Britain

Personalised recommendations