[Importance of preanalytical step in hemostasis].

The preanalytical conditions are the major component to assure the reliability and validity of results in hemostasis. They extend from the requirement of analysis, patient preparation, blood collection and the conditions of transport, centrifugation and plasma storage until analysis. They are the most important sources of erroneous or inconclusive results; mainly the quality of the analytical stage has seen great progress of instruments and reagents. Control and standardization efforts of these preanalytical conditions are essential to ensure the quality of exploration in hemostasis.