Lਅਔਔਅ਒ ਔਏ ਔਈਅ E਄ਉਔਏ਒ Alterations in plasma protein C activity levels following apheresis platelet donation and whole blood donation Frances Duggan1, Kathleen O'Sullivan2, Joan P. Power1, Michael Healy3, William G. Murphy4 Irish Blood Transfusion Service, Munster Regional Transfusion Centre, St. Finbarr's Hospital, Cork; 2Department of Statistics, University College Cork, Cork; 3Department of Biological Sciences, Cork Institute of Technology, Bishopstown, Cork; 4Irish Blood Transfusion Service, National Blood Centre, Dublin, Ireland 1

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Independent two-sample t-tests were used to test for statistically significant differences between groups for all parameters. Donor groups did not differ at baseline (p>0.05) for measurements of APTT, fibrinogen, protein C activity, free protein S, vWF Ag, sP-selectin, ADAMTS-13 activity, haemoglobin level and age. There were statistically significant differences between groups for baseline values of PT (p=0.038), and sE-selectin (p=0.018). Analyses of changes within groups. There were statistically significant differences (by repeated measures ANOVA) between the three time points for protein C activity (p=0.002), and vWF Ag (p=0.014) within the plateletpheresis donor group. (Table Ia). In the group of males who donated whole blood there were statistically significant differences between the three time points for protein C activity (p=0.011), sP-selectin (p