Inherited platelet defects are a rare and heterogeneous group of disorders. The majority of affected patients present with mild to moderate bleeding tendencies. However, in trauma and surgery, bleeding may be difficult to control. Laboratory tests for diagnosis are necessary for the prevention and treatment of critical bleeding. The aim of the THROMKID study was to obtain information on the means of investigating platelet function employed by clinical centres in German-speaking countries. For this purpose a patterns-of-practice survey was conducted from 2005 to 2007, the results of which are reported here. A total of 37 out of 41 identified clinical centers serving 98 million people completed the survey questionnaire. The number of tests offered for assessment of platelet function varied between 1 and 11, median 4. Aggregometry continued to be the most popular and helpful technique for evaluation of suspected platelet function disorders (100%). The PFA-100(R) CT (76%) and in vivo bleeding time (54%) were used to screen patients with suspected platelet function disorders. Selection of tests was based on a case-by-case decision at most centres (82%). The majority of centres performed specific platelet function tests less than 50 times per month. This survey illustrates the preferences of clinical centres in the selection, performance and interpretation of platelet function tests. These practices may considerably influence the detection and diagnosis of platelet function disorders. There is an urgent need for existing tests to be improved and new, fast and reliable tests of platelet function to be developed.