Semin Thromb Hemost 2002; 28(3): 247-256
DOI: 10.1055/s-2002-32658
Copyright © 2002 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel.: +1(212) 584-4662

Coagulation and Chromogenic Assays of Factor VIII Activity: General Aspects, Standardization, and Recommendations

Trevor W. Barrowcliffe, Sanjeev Raut, Dawn Sands, Anthony R. Hubbard
  • National Institute for Biological Standards and Control, Potters Bar, United Kingdom
Further Information

Publication History

Publication Date:
04 July 2002 (online)

ABSTRACT

Factor VIII (FVIII) is assayed by one-stage and two-stage clotting methods and by chromogenic methods, although the chromogenic method has largely replaced the two-stage clotting assay. Clinical plasma samples are assayed mostly by one-stage assays, but most manufacturers of concentrates use the chromogenic method, which is more precise and is the reference method of the European Pharmacopoeia and the International Society on Thrombosis and Haemostasis (ISTH). For most plasma-derived concentrates, assays against the World Health Organization (WHO) concentrate standard give similar results with the one-stage and chromogenic methods, but for products produced by the ``method M'' monoclonal antibody process, the one-stage potency is 25 to 30% higher than the chromogenic potency. For full-length recombinant products assayed against a plasma-derived concentrate standard, one-stage potencies are about 10% lower than chromogenic potencies, but for the B-domain deleted recombinant product ReFacto®, the discrepancy is larger-from 20 to 50%. These discrepancies emphasize the need for an international methodology for labeling of concentrates. In ex vivo assays of hemophilic plasmas after infusion of concentrates, large discrepancies are found among laboratories and with different assay methods when a plasma standard is used. In most studies, the chromogenic potencies are higher than the one-stage potencies, and the discrepancy is highest for recombinant products. This discrepancy can be largely eliminated by the use of concentrate standards, diluted in FVIII-deficient plasma, to assay postinfusion plasma samples.

REFERENCES

  • 1 Over J. Methodology of the one-stage assay of factor VIII (VIII:C).  Scand J Haematol . 1984;  33(Suppl 41) 13-24
  • 2 Barrowcliffe T W. Methodology of the two-stage assay of Factor VIII (VIII:C).  Scand J Haematol . 1984;  33(Suppl 41) 25-38
  • 3 Rosén S, Friberger P, Andersson M, Vinazzer H. A new chromogenic assay for determination of human factor VIII:C activity. In: Triplett DA, ed. Advances in Coagulation Testing Skokie, IL: College of American Pathologists 1986: 255-260
  • 4 Barrowcliffe T W. Comparisons of 1-stage and 2-stage assays of factor VIII:C. In: Nilsson I-M, Barrowcliffe TW, Schimpf K, eds. Factor VIII Concentrates and their Clotting Activity Scand J Haematol 1984 33(Suppl 41): 39-54
  • 5 Barrowcliffe T W. The one-stage versus the two-stage factor VIII assay. In: Triplett DA, ed. Advances in Coagulation Testing Skokie, IL: College of American Pathologists 1986: 47-62
  • 6 Hubbard A R, Curtis A D, Barrowcliffe T W. Assay of factor VIII concentrates: comparison of chromogenic and 2-stage clotting assays.  Thromb Res . 1986;  44 887-891
  • 7 Barrowcliffe T W. Standardization and assay.  Semin Thromb Hemost . 1993;  19 73-79
  • 8 Dawson N J, Kemball-Cook G, Barrowcliffe T W. Assay discrepancies with highly purified factor VIII concentrates.  Haemostasis . 1989;  19 131-137
  • 9 Lee M L, Magalang E A, Kingdon H S. An effect of predilution on potency assays of factor VIII concentrates.  Thromb Res . 1983;  30 511-519
  • 10 Barrowcliffe T W, Factor VIII and Factor IX Sub-committee. Recommendations for the assay of high-purity factor VIII concentrates.  Thromb Haemost . 1993;  70 876-877
  • 11 Raut S, Heath A B, Barrowcliffe T W. A collaborative study to establish the 6th International Standard for Factor VIII concentrate.  Thromb Haemost . 2001;  85 1071-1078
  • 12 Albertengo M E, Barrowcliffe T W, Oliva L, Bevan S, Raut S. New recombinant standard for FVIII concentrate gives same results as previous plasma derived standards on a range of FVIII products.  Thromb Haemost . 2000;  83 789-790
  • 13 Barrowcliffe T W, Watton J, Tubbs J E, Harman A, Kemball-Cook G. Potency of high purity factor VIII concentrates (Letter).  Lancet . 1990;  2 124
  • 14 Hubbard A R, Weller L J, Bevan S A. A survey of one-stage and chromogenic potencies in therapeutic FVIII concentrates (in press).  Br J Haematol. 2002; 
  • 15 Mikaelsson M, Oswaldsson U, Sandberg H. Influence of phospholipids on the assessment of factor VIII activity.  Haemophilia . 1998;  4 646-650
  • 16 Kirkwood T BL, Barrowcliffe T W. Discrepancy between 1-stage and 2-stage assay of factor VIII:C.  Br J Haematol . 1978;  40 333-338
  • 17 Lee C A, Owens D, Bray G. Pharmacokinetics of recombinant factor VIII (Recombinate) using one-stage clotting and chromogenic factor VIII assay.  Thromb Haemost . 1999;  82 1644-1647