[Primary hemostasis exploration].

Primary hemostasis exploration involves many tests, but most of them are highly specialized. Meanwhile, a few simple and reliable assays can make possible a first orientation of the diagnosis in a routine laboratory. This review is organized in four parts. It highlights the importance of pre-analytical steps when exploring hemostasis, especially a carefully conducted clinical history and blood collecting conditions. It first presents the tests involved in the global exploration: the platelet count, the bleeding time, the occlusion time and the prothrombin consumption test. Then, this review presents the tests essential for the diagnosis of thrombocytopenia, von Willebrand disease and platelet disorders. Finally, we discussed about the limits and the future of diagnosis in primary hemostasis, and more particularly about endothelial cells and the adhesion proteins that are implicated.