Assessment of platelet function in applications for marketing authorisation

Background: There are no methods in official guidance documents which presc ribe how to check platelet function in platelet concentrates for transfusio n. It is therefore extremely difficult to compare results from different la boratories; the test procedures differ too much. This creates special probl ems for the assessment of the quality of platelet concentrates in applicati ons for marketing authorisation, which are submitted to the Paul-Ehrlich-In stitut. Material and Methods: Data were obtained from 56 applications grant ed for marketing authorisation from 30 German blood banks. The four differe nt kinds to produce platelet concentrates (apheresis, buffy coat-derived si ngle donor/pooled platelets as well as platelet-rich plasma) were implicate d. Platelet function tests used were aggregometry, flow cytometry, hypotoni c shock resistance and thrombelastography. If possible, the submitted resul ts were evaluated statistically. Results: Though it was difficult to statis tically evaluate the available data, the following parameters seem to be su itable to test the quality of platelet concentrates because they show diffe rences in single functional parameters during storage: aggregation, express ion of CD62P - with and without stimulation - measured by flow cytometry, h ypotonic shock resistance. For test performance it is important to use suit able concentrations of stimulants, antibodies and cell counts. Conclusion: It is absolutely necessary to establish obligatory, standardised and valida ted methods for in vitro testing of platelet function to be able to compare quality of platelet concentrates and thus to guarantee an equally high sta ndard in all German blood banks.