title: WBC reduction in RBC concentrates by prestorage filtration: multicenter experience.
abstract: BACKGROUND
  As universal leukocyte (WBC) reduction (ULR) is being considered as a new standard, few data are available on the performance of WBC-reduction filtration in routine practice. The performance of WBC-reduction in RBCs, using varied filtration practices, in meeting the current FDA requirement (<5 x 10(6)), Council of Europe (EC) recommendation, the proposed FDA requirement (<1 x 10(6)), and a more stringent proposal (<5 x 10(5)) for residual WBCs per RBC unit was assessed and compared.
  
  
  METHODS
  Participating facilities were the 11 sites of the Viral Activation Transfusion Study (VATS), a prospective study of the impact of transfusion with and without WBC-reduction on survival and HIV viral load in HIV-1-infected patients. Patients randomly assigned to undergo WBC reduction were required to receive RBCs < or =14 days old that had undergone prestorage (within 72 hours of collection) WBC-reduction filtration by a method devised to achieve a postfiltration WBC count of <5 x 10(6). Residual WBC quantitation was performed by PCR in the central VATS laboratory by using frozen WBC-reduced RBC samples obtained at issue for transfusion.
  
  
  RESULTS
  A total of 1869 WBC-reduced RBC units were studied. Filtration practices varied within and between sites. There were significant differences in mean residual WBC counts at the 11 sites (p<0.001). Among the WBC-reduced RBC units, 0.8 percent exceeded 5 x 10(6) WBCs per unit, 8.3 percent exceeded 1 x 10(6) WBCs per unit, and 14.3 percent exceeded 5 x 10(5) WBCs per unit.
  
  
  CONCLUSIONS
  Residual WBCs in WBC-reduced RBC units vary within and between sites. WBC reduction was successful, in that over 99 percent and 91 percent of VATS WBC-reduced RBC units met US and EC thresholds, respectively. However, the small but measurable failure rate indicates that not every unit will meet these guidelines.
authors.affiliation: Blood Bank-Transfusion Medicine Service, University Hospitals of Cleveland, Cleveland, Ohio 44106, USA. ryomtovian@yahoo.com
authors.forename: R
authors.initials: R
authors.lastname: Yomtovian
authors.forename: T
authors.initials: T
authors.lastname: Gernsheimer
authors.forename: S F
authors.initials: SF
authors.lastname: Assmann
authors.forename: K
authors.initials: K
authors.lastname: Mohandas
authors.forename: T H
authors.initials: TH
authors.lastname: Lee
authors.forename: L A
authors.initials: LA
authors.lastname: Kalish
authors.forename: M P
authors.initials: MP
authors.lastname: Busch
mesh_terms: D001781:Blood Component Removal / Q000379:methods* / Q000592:standards; D001793:Blood Preservation / Q000379:methods / Q000592:standards; D017707:Erythrocyte Transfusion / Q000379:methods* / Q000592:standards; D005374:Filtration / Q000379:methods; D015658:HIV Infections / Q000628:therapy; D006801:Humans; D007958:Leukocyte Count; D007962:Leukocytes; D013696:Temperature; D013997:Time Factors