Platelet function testing in apheresis products: flow cytometric, resonance thrombographic (RTG) and rotational...

During storage of platelet concentrates, quality control of the units is mandatory. This includes the important testing of the hemostatic function of platelets. So far, mostly platelet aggregation analyses have been performed. In this study, new approaches were tested to evaluate the applicability of modern techniques for quality monitoring. Plateletpheresis was performed with two different cell separators (AMICUS cell separator, Fenwal, Baxter Healthcare, Deerfield, USA; COBE Spectra, COBE BCT, Lakewood, USA). In each procedure split products (n = 22) were prepared and stored for 1-2 days (n = 22) or 3 5 days (n = 22). Platelet hemostatic capacity was tested by applying flow cytometry. platelet aggregation (platelet-rich-plasma [PRP]+agonist), resonance thrombography (RTG; PRP, no agonist) and rotational thrombelastography (roTEG; PRP+agonist). Flow cytometric analyses did not reveal significant changes in structural (CD41a. CD42b) or activation-dependent antigens (CD62p, CD63, LIBS, RIBS). Also, differences in the data from the flow cytometric reactivity tests were not significant between the two groups. In platelet aggregation assays, shape change (p = 0.8), maximum aggregation (p = 0.4), and maximum gradient (p = 0.8) did not show significant differences between the two groups. In the RTG test, differences between r-time (reaction time; p = 0.4), and f-time (clot formation time [fibrin influence]; p = 0.3), and in roTEG r-time (coagulation time; p = 0.1) and k-time (clot formation time; p = 1.0) were not significant. P-time (clot formation time [platelet influence]) and M (maximum amplitude) in RTG, and k-time and MA (maximum amplitude) in roTEG showed a slight decrease in platelet function (p < or = 0.05). We conclude that platelet function is well maintained during storage. This is reflected by the results of immunological and platelet function assays. Rotational thrombelastography (in the case of PRP) and especially resonance thrombography represent promising methods for quality control of platelet concentrates and rapidly provide information about the status of platelet function and the whole clotting process.