Diagnosis of the Prethrombotic State. Introduction

The purpose of this symposium is to highlight new developments in methods that may detect patients with increased risk for arterial or venous thrombosis. Some of the techniques presented rely on the presence of changed clotting factors, fibrinogen in particular, or of released peptides. A novel approach is the use of antibodies directed specifically against complexes of inhibitors with activated factors.

Blood platelets play an important role particularly in arterial thrombosis.Radio-immuno-assays have been worked out for two secretion products from platelets: platelet factor 4 and beta-thromboglobulin. Theoretically the sensitivity of these tests will be limited by the short half life of the substances. A possible useful approach is therefore the study of the properties of released platelets since it has been demonstrated that these platelets may have a normal survival. The platelet coagulant activity as predictor of thrombosis may fit in here. Other properties of released platelets such as the exposure of actin or the decreased uptake of serotonin are currently under investigation. Spontaneous aggregation in vivo or in vitro as well as a short half life of labeled platelets has been found in various thromboembolic diseases.

The predictive value of various tests should be evaluated in prospective studies. An example of such an approach is given in the paper that concludes the symposium.