title: Microparticle profile and procoagulant activity of fresh-frozen plasma is affected by whole blood leukoreduction rather than 24-hour room temperature hold.
abstract: BACKGROUND
  Microparticles (MPs) are small phospholipid-containing vesicles that have procoagulant properties. MPs are thought to contribute to the hemostatic potential of plasma. This study investigated the effects of whole blood (WB) hold time and leukoreduction (LR) on the MP profile and hemostatic potential of fresh-frozen plasma (FFP).
  
  
  METHODS
  WB units (n=12) from healthy donors were divided into two pairs and each pair was held at 20 to 24°C for 6 or 24 hours. At the designated hold time, 1 unit from the pair was LR while the other unit was not LR. FFP was prepared by standard procedures, aliquoted, and frozen. The MP content was determined by flow cytometry using an absolute count assay and specific labels for red blood cells (CD235a), platelets (CD41), and phosphatidylserine (PS). The hemostatic potential was determined by thrombelastography (TEG) and coagulation factor assays.
  
  
  RESULTS
  Compared to non-LR-FFP, LR-FFP had significantly lower numbers of MPs, particularly CD41+ MPs and PS-positive MPs (p<0.03). LR-FFP, compared to non-LR-FFP, had a slower clot formation time (p=0.002); lower clot strength (p<0.001); and lower Factor (F)VIII, FXII, and fibrinogen levels (p<0.01). With longer WB hold time, the TEG profile was unchanged, although FVIII levels were decreased as expected (p<0.01). On average FFP units met quality requirements.
  
  
  CONCLUSIONS
  LR of WB resulted in lower hemostatic potential of FFP in conjunction with depletion of MPs and coagulation factors. Longer WB hold time did not significantly affect the hemostatic potential of FFP as measured by TEG. Acceptable hemostatic quality was maintained for all FFP processing conditions studied.
authors.affiliation: Research and Development, Australian Red Cross Blood Service, Melbourne, Victoria, Australia.
authors.forename: Kasey Sze-Kei
authors.initials: KS
authors.lastname: Chan
authors.forename: Rosemary L
authors.initials: RL
authors.lastname: Sparrow
mesh_terms: D000328:Adult; D001772:Blood Cell Count; D001792:Blood Platelets / Q000737:chemistry / Q000502:physiology; D001793:Blood Preservation / Q000379:methods*; D055252:Cell-Derived Microparticles; D005169:Factor VIII / Q000032:analysis; D005176:Factor XIII / Q000032:analysis; D005340:Fibrinogen / Q000032:analysis; D005374:Filtration; D005434:Flow Cytometry; D006487:Hemostasis; D006801:Humans; D047589:Leukocyte Reduction Procedures; D008297:Male; D008563:Membrane Lipids / Q000097:blood; D008875:Middle Aged; D010718:Phosphatidylserines / Q000097:blood; D010949:Plasma / Q000166:cytology / Q000502:physiology*; D013696:Temperature; D013916:Thrombelastography
chemical_list: D008563:Membrane Lipids; D010718:Phosphatidylserines; C078147:F8 protein, human; D005169:Factor VIII; D005340:Fibrinogen; D005176:Factor XIII