title: The effect of methylene blue photoinactivation and methylene blue removal on the quality of fresh-frozen plasma.
abstract: BACKGROUND
  T: he effects of using fresh or frozen-thawed plasma, WBC reduction of plasma before freezing, and the use of two different methylene blue (MB) removal filters on the quality of MB-treated plasma were compared.
  
  
  METHODS
  In a paired study (n = 11/arm) plasma was frozen within 8 hours of collection, thawed, MB photoinactivated, and then filtered using one of two MB removal filters. Fresh plasma (n = 16) and plasma WBC reduced before freezing (n = 19) were MB inactivated.
  
  
  RESULTS
  Freeze-thawing resulted in loss of activity of FXII and VWF of 0.06 and 0.04 units per mL, respectively, but no significant loss of activity of factors II through XI or fibrinogen. Further loss of activity occurred after MB treatment: FII (0.07 IU/mL), FV (0.11 U/mL), FVII (0.08 IU/mL), FVIII (0.28 IU/mL), F IX (0.12 IU/mL), FX (0.16 IU/mL), FXI (0.28 U/mL), FXII (0.15 U/mL), VWF antigen (0.05 IU/mL), VWF activity (0.06 U/mL), and fibrinogen (0.79 g/L). Losses due to this step were significantly (5-10%) lower in fresh plasma compared to frozen-thawed plasma. Neither MB removal filter resulted in significant loss of activity of any factor studied.
  
  
  CONCLUSIONS
  MB removal, by either of the available filters, has little impact on the coagulation factor content of plasma, but freezing of plasma before MB treatment results in a small additional loss.
authors.affiliation: National Blood Service, England & North Wales, United Kingdom.
authors.forename: Margaret
authors.initials: M
authors.lastname: Garwood
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Cardigan
authors.forename: Olive
authors.initials: O
authors.lastname: Drummond
authors.forename: Valerie S
authors.initials: VS
authors.lastname: Hornsey
authors.forename: Craig P
authors.initials: CP
authors.lastname: Turner
authors.forename: David
authors.initials: D
authors.lastname: Young
authors.forename: Lorna M
authors.initials: LM
authors.lastname: Williamson
authors.forename: Chris V
authors.initials: CV
authors.lastname: Prowse
mesh_terms: D001777:Blood Coagulation; D001779:Blood Coagulation Factors / Q000378:metabolism; D001793:Blood Preservation; D007562:Creutzfeldt-Jakob Syndrome / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission; D015925:Cryopreservation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005374:Filtration; D006801:Humans; D017053:Infection Control; D007962:Leukocytes; D008751:Methylene Blue / Q000494:pharmacology*; D010777:Photochemistry; D010949:Plasma / Q000187:drug effects* / Q000378:metabolism; D012307:Risk Factors
chemical_list: D001779:Blood Coagulation Factors; D004791:Enzyme Inhibitors; D008751:Methylene Blue