title: Prestorage leukoreduction and low-temperature filtration reduce hemolysis of stored red cell concentrates.
abstract: BACKGROUND
  Universal prestorage leukoreduction in Canada created the perception that stored red cells (RBCs) are more hemolyzed than their unfiltered predecessors. A pool-split design tested the effects of leukoreduction on hemolysis of stored RBCs.
  
  
  METHODS
  Two ABO-matched units were pooled, divided, and then processed into leukoreduced (LR) and nonleukoreduced (NLR) units with the Pall LT-WB or RC-PL systems and sampled during standard processing and storage for testing of sterility, counts, hemolysis, and osmotic fragility.
  
  
  RESULTS
  Room temperature (RT) filtration of 10 pairs of LT-WB-LR and -NLR units showed significantly different percentage of hemolysis (0.39%) and osmotic fragility (0.643%) at 42 days. Cold-stored and -filtered units (2 days at 4 degrees C before processing) were less hemolyzed, but showed a similar proportional decrease of hemolysis in LR units (0.13% vs. 0.25% at 42 days). RBCs from RC-PL systems showed the lowest hemolysis although there was a filtration effect (0.05% vs. 0.12%, 42 days). Osmotic fragility paralleled hemolysis. Segment samples gave inaccurate results. Two-day prefiltration cold storage reduced hemolysis from 0.36 to 0.07 percent (42 days, p < 0.001). RT-LR hemolysis became significantly higher by Day 10 and 4 degrees C LR by Day 12. NLR units showed hemolysis by Day 7. LR units filtered cold were less hemolyzed (p < 0.05) than RT-LR but osmotic fragility was unchanged.
  
  
  CONCLUSIONS
  LR-RBCs prepared by any of three methods (LT-WB, RT or cold; RC-PL), filtered at 4 degrees C, were less hemolyzed during storage than nonfiltered concentrates: 4 degrees C leukoreduction is beneficial for RBCs and does not cause hemolysis or enhance fragility.
authors.affiliation: Research and Development, Canadian Blood Services, Vancouver, British Columbia, Canada. Maria.Issa@bloodservices.ca
authors.forename: M I C
authors.initials: MI
authors.lastname: Gyongyossy-Issa
authors.forename: S L
authors.initials: SL
authors.lastname: Weiss
authors.forename: S O
authors.initials: SO
authors.lastname: Sowemimo-Coker
authors.forename: R B
authors.initials: RB
authors.lastname: Garcez
authors.forename: D V
authors.initials: DV
authors.lastname: Devine
mesh_terms: D001793:Blood Preservation; D003080:Cold Temperature; D005374:Filtration; D006461:Hemolysis; D006801:Humans; D047589:Leukocyte Reduction Procedures; D009996:Osmotic Fragility