The impact of whole blood processing and freezing conditions on the quality of therapeutic plasma prepared from whole blood

BackgroundThe quality of whole blood (WB)-derived plasma preparations has been the subject of several studies, but there has been a lack of robust, comparative data for the different methods of processing and freezing. Study Design and MethodsSix WB-derived plasma units were pooled and split (n=16) and frozen within either 8 or 24 hours after WB collection, stored at 4 degrees C or at room temperature (RT), and then frozen either slowly at -20 degrees C or rapidly to below -30 degrees C. Plasma units were tested for fibrinogen, Factor (F)V, FVII, FVIII, FXI, and von Willebrand factor (VWF), protein C (PC), protein S (PS) activity and free PS, prothrombin time, and partial thromboplastin time. ResultsFVIII was reduced by 9% to 19% after having been stored for 24 hours irrespective of storage temperature. Slow freezing (SF) reduced FVIII by 17% to 25% compared to rapid freezing (RF) to below -30 degrees C. Storage temperature, but not 24-hour storage, decreased PS activity by 20% to 28%. PS activity was 8% to 17% lower in plasma units frozen slowly compared to RF. Storage and freezing had no influence on free PS. SF caused small losses of FVII and FXI activity. ConclusionTwenty-four-hour hold at RT and SF both reduce FVIII levels below 70U/dL in many plasma units. PS activity is affected substantially by storage temperature and SF, but free PS is not. With regard to plasma quality, freezing to below -30 degrees C within 1 hour is superior to SF at -20 degrees C.