[Exploration of hemostasis in current practice].

The exploration of coagulation in biological practice implies simple routine tests. A normal bleeding time associated with a normal platelet count allows to exclude any primary haemostasis abnormality. A prolonged bleeding time is most frequently the result of a thrombocytopenia, the etiology of which remains to be determined. A prolonged bleeding time is also observed in von Willebrand disease and in thrombopathia. Such diagnosis requires appropriate investigation. The exploration of the coagulation cascade includes prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen level. A congenital or acquired deficiency in one or more coagulation factors should be distinguished from a lupus anticoagulant or from the occurrence of an antibody against a coagulation factor. Indeed, a prolonged APTT is not always related to a bleeding risk. Only the identification of the coagulation abnormality can predict the bleeding or thrombotic risk during surgery. In each case, an appropriate preventive therapy should be prescribed.