[Perioperative coagulation diagnostics].

The main diagnostic tool for the preoperative identification of patients with an increased risk of bleeding or thrombosis is the patient history. Laboratory diagnostics should only be performed if a bleeding diathesis is suspected from patient history or clinical symptoms of bleeding, or if an adequate patient history cannot be performed. Measurement of prothrombin time, aPTT, or bleeding time as a general preoperative screening procedure is neither cost-effective nor efficient for the identification of patients with increased bleeding risk. Normal values of prothrombin time and aPTT do not exclude the most prevalent bleeding disorder, von Willebrand's disease. A normal platelet count does not exclude a severe platelet function defect. Selection of specific laboratory assays is performed on the basis of the individual patient history and clinical picture; laboratory 'profiles' can be defined for some specific clinical conditions. In some cases, patients should be referred to a specialized coagulation clinic for further diagnostics and treatment planning. Preoperative laboratory diagnostics for thrombophilia are not necessary in most cases. The decision for intensified antithrombotic measures is made according to patient history and the postoperative clinical course.