A reunification of the US (“NIH”) and International Unit into a single standard for Thrombin

 

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Summary

The existence of two different units forThrombin in widespread international use has caused confusion for many years. The holders of the WHO International Standard (IS) for Alpha Thrombin and the US Standard (also known as the “NIH Standard”) now report on a collaboration to reunite the International Unit (IU) and the US unit (“NIH unit”).A study was organised involving 25 laboratories in 15 countries to investigate the possibility of preparing a common Standard with a common unit and to investigate aspects of methodology that cause divergence of results using the IS and US Standard. Laboratories were asked to measure the potency of two candidate replacement standards (C, 01/578 and D, 01/580), and potencies were calculated relative to both the existing US Standard (lot J) and the IS (89/588). Data analysis of a total of 128 assays indicated that sample D would make an ideal replacement joint Standard with a potency of 110 IU/ampoule (equivalent to 110 US units per ampoule) based on data from clotting assays. No significant differences in results were observed using fibrinogen of human or bovine origin, or using human plasma. Comparisons of chromogenic and clotting assays indicated that sample D had a similar high proportion of alpha thrombin to the current IS for Alpha Thrombin (89/588). Sample D was adopted as the IS for Thrombin (01/580) and the US Standard (lot K) with a potency of 110 IU/ampoule.

• References

• 1 Gaffney PJ, Heath AB, Fenton JW. A collaborative study to establish an international standard for alphathrombin.. Thromb Haemost 1992; 67: 424-7.
  Article in Thieme ConnectPubMedGoogle Scholar
• 2 Fenton JW, Fasco MJ, Stackrow AB. et al Human thrombins. production, evaluation, and properties of α -Thrombin.. J Biol Chem 1977; 252: 3587-98.
  CrossrefPubMedGoogle Scholar
• 3 Gaffney PJ, Edgell TA. The International and "NIH" units for thrombin--how do they compare?. Thromb Haemost 1995; 74: 900-3.
  Article in Thieme ConnectPubMedGoogle Scholar
• 4 Hockin MF. et al A model for the stoichiometric regulation of blood coagulation.. J Biol Chem 2002; 277: 18322-33.
  CrossrefPubMedGoogle Scholar
• 5 Walsh RC, Armstrong PW. A marriage of enhancement: fibrinolysis and conjunctive therapy.. Thromb Haemost 2004; 92: 1194-200.
  Article in Thieme ConnectPubMedGoogle Scholar
• 6 Nesheim M. Thrombin and fibrinolysis.. Chest 2003; 124: 33S-9S.
  CrossrefPubMedGoogle Scholar
• 7 Clark RA. Fibrin glue and wound repair: facts and fancy.. Thromb Haemost 2003; 90: 1003-6.
  Article in Thieme ConnectPubMedGoogle Scholar
• 8 Lundblad RL. et al A review of the therapeutic uses of thrombin.. Thromb Haemost 2004; 91: 851-60.
  Article in Thieme ConnectPubMedGoogle Scholar
• 9 Finney D.. in Statistical methods in biological assay., 3rd edn. Charles Griffen. London: 1978
  Google Scholar
• 10 Kirkwood TBL. Geometric means and measure of dispersion.. Biometrics 1979; 35: 908-9.
  PubMedGoogle Scholar
• 11 Kirkwood TB, Tydeman MS. Design and analysis of accelerated degradation tests for the stability of biological standards II. A flexible computer program for data analysis.. J Biol Stand 1984; 12: 207-1.
  CrossrefPubMedGoogle Scholar