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...