Distinct sequences of the glycoprotein Ib-binding domain of von Willebrand factor involved in shear induced platelet aggregation

Platelet aggregometry is an important technique which is frequently used by hemostaseologists and researchers. Gustav Born introduced the principle more than 40 years ago. Many different ways to perform aggregometry have been published. The results of aggregometry may become more comparable if some rules would be generally accepted. (1) The pre-analytical procedures are probably the most important factors which influence aggregometry results. Besides correct blood sampling important factors are the preparation of platelet-rich plasma (PRP), incubation of the PRP at room temperature and awareness of time-dependent changes of aggregometry results. (2) A major point concerns the agonists. Agonists of different sources have to be compared to verify that they lead to the expected results. Even different salts of ADP lead to different results and different collagen preparations lead to a large variation of aggregation response (3). The frequently used procedure of adjusting the platelet number in the PRP is cumbersome, affects platelet activation and is not necessary. (4) Aggregometers should comply with some simple rules. The changes in optical density should be linearized so that – if this is required – percentages can be given. The recorder speed should be standardized and all recorders should provide 1?cm/min. Calibration of the aggregometer sensitivity should be possible. (5) If aggregometry is used to define the response to antiaggregating agents agreement on the inducer concentrations is essential. If some rules are applied aggregometry is a relatively simple and reliable method, and well suited for clinical studies and for experimental research.