title: The dynamics of clot formation in fresh-frozen plasma.
abstract: BACKGROUND
  Factor VIII (FVIII) levels are used as a quality marker of fresh-frozen plasma (FFP); however, other clotting factors are not routinely measured.
  
  
  METHODS
  We assessed additional haemostatic parameters and the dynamics of coagulation using Thrombelastography (TEG) and a thrombin generation test (TGT). FFP was prepared on the day of donation (Day 0) or after overnight hold at 4 degrees C (Day 1).
  
  
  RESULTS
  Factor VIII in Day 1 FFP was 18% lower than in Day 0. TEG parameters in Day 1 FFP were consistent with increased coagulability and did not correlate with altered levels of clotting factors, but were consistent with the increased levels of microparticles seen in the Day 1 samples. TGT studies exhibited increased lag time, time to peak and reduced peak thrombin generation, but no change in endogenous thrombin potential (ETP) on Day 1. There was a weak association between FVIII level and both ETP and peak thrombin (ETP r(s)> or = 0.22, P< or = 0.003; peak thrombin r(s)> or = 0.48, P< or = 0.0001), which was influenced by ABO group, with the lowest levels in group O.
  
  
  CONCLUSIONS
  We conclude that levels of FVIII do not predict the haemostatic potential of FFP and that there may be a role for alternative technologies in monitoring the quality of FFP.
authors.affiliation: Haemostasis Research Unit, Department of Haematology, University College London, London, UK. andrew.lawrie@ucl.ac.uk
authors.forename: A S
authors.initials: AS
authors.lastname: Lawrie
authors.forename: R A
authors.initials: RA
authors.lastname: Cardigan
authors.forename: L M
authors.initials: LM
authors.lastname: Williamson
authors.forename: S J
authors.initials: SJ
authors.lastname: Machin
authors.forename: I J
authors.initials: IJ
authors.lastname: Mackie
mesh_terms: D001777:Blood Coagulation / Q000502:physiology*; D005169:Factor VIII / Q000032:analysis*; D006801:Humans; D010949:Plasma / Q000737:chemistry / Q000502:physiology*; D011786:Quality Control; D013916:Thrombelastography
chemical_list: D005169:Factor VIII