This volume contains all relevant information discussed in a Workshop on
thromboplastin calibration held in Leiden, The Netherlands on July 1,
1983. The Workshop was an initiative of the Dutch foundation for a
Reference Laboratory for Anticoagulant Control (RELAC) and it was
organized by the Boerhaave Committee for postgraduate teaching of the
Faculty of Medicine of the University of Leiden. The Workshop was held
under the auspices of five organizations i. e. the European Community
Bureau of Refer- ence (BCR), the European Committee for Clinical
Laboratory Standards (ECCLS), the International Association of
Biological Standardization (lABS), the International Committee for
Standar- dization in Haematology (ICSH), -and the International
Committee on Thrombosis and Haemostasis (ICTH). The aim of the Workshop
was to discuss and develop a method for calibration of reagents, i. e.
thromboplastins and/or plasmas used for the prothrombin time. During the
Workshop three recent thromboplastin calibration studies were discussed,
the results of which are presented in chapters 4, 7 and 9. These studies
were carried out on the basis of a new calibration model developed by
experts working with BCR and WHO. The usefulness of this model and the
standardization system based on it is the leading thread running through
this volume. Statisticians and clinicians discuss the results from a
scientific point of view. Thromboplastin manufacturers, for whom
especially the use of the model and the system is intended, discuss the
matter also from an economic and legal point of view.