Thromb Haemost 1979; 42(04): 1230-1239
DOI: 10.1055/s-0038-1657018
Original Article
Schattauer GmbH Stuttgart

In Vivo Recovery of Factor VIII: A Comparison of One-Stage and Two-Stage Assay Methods

Authors

  • I M Nilsson

    The Coagulation Laboratory, General Hospital, Malmö, Sweden
  • T B L Kirkwood

    *   National Institute for Biological Standards and Control, London NW3 6RB, England
    The Coagulation Laboratory, General Hospital, Malmö, Sweden
  • T W Barrowcliffe

    *   National Institute for Biological Standards and Control, London NW3 6RB, England
    The Coagulation Laboratory, General Hospital, Malmö, Sweden
Further Information

Publication History

Received 12 December 1978

Accepted 10 February 1979

Publication Date:
23 August 2018 (online)

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Summary

The recovery and half-life of VIII: C in the plasma of severely haemophilic patients was measured by one-stage and two-stage assays after injection of two Factor VIII concentrates (Hemofil, Hyland and Fraction I-O, Kabi). Plasma volumes were measured with an Evans� Blue technique, and both concentrates and post-infusion samples were measured against the same plasma standard.

There was a highly significant difference in recoveries estimated by the two assay methods. The one-stage assays gave the most consistent results, in that the average recovery was 100%, whereas the two-stage assays gave only about 80% of the value expected from in vitro assays. There was no difference in recoveries between the two concentrates.

The two-stage assays gave a slightly shorter half-life than the one-stage assays, and the half-life of Hemofil was also shorter than that of Fraction I-O.