title: Particulate matter phenomenon: adverse event data and the effect of leukofiltration.
abstract: BACKGROUND
  In February 2002, a multiorganizational task force investigated blood center reports of unusual particulate matter (PM) visible in packed red blood cells (RBC). A cohort study assessed increase in adverse events (AEs) related to this phenomenon, as well as the effect of post-leukofiltration (LF) on PM.
  
  
  METHODS
  Two blood centers assessed AEs in patients transfused with RBCs having visible PM (classified as normal by-products of RBC preparation), PM RBCs subsequently LF, or RBCs without visible PM, and the effect of LF on PM removal.
  
  
  RESULTS
  There was no difference in AEs in patients transfused with PM RBCs with or without LF compared to patients transfused with RBCs without visible PM. Subsequently filtered PM RBCs had acceptable residual WBC counts and median platelet removal of 92%.
  
  
  CONCLUSIONS
  Transfusion of RBCs with visible PM or RBCs subsequently LF does not appear to increase the risk of an AE. LF use on PM RBCs results in the PM removal without adversely affecting filter performance. The lack of evidence of an increase in AE reports does not mean that there is no effect, and there may be a baseline AE rate attributable to PM which has not been thoroughly researched.
authors.affiliation: Division of Blood Applications, FDA, CBER, OBRR, Rockville, Maryland, USA. Orton@cber.fda.gov
authors.forename: Sharyn L
authors.initials: SL
authors.lastname: Orton
authors.forename: G F
authors.initials: GF
authors.lastname: Leparc
authors.forename: Susan
authors.initials: S
authors.lastname: Rossmann
authors.forename: R M
authors.initials: RM
authors.lastname: Lewis
mesh_terms: D001781:Blood Component Removal; D001800:Blood Specimen Collection; D015331:Cohort Studies; D017707:Erythrocyte Transfusion / Q000009:adverse effects*; D005374:Filtration; D006801:Humans; D007962:Leukocytes