title: The effect of donor red cell sedimentation rate on efficiency of granulocyte collection by centrifugal leukapheresis.
abstract: BACKGROUND
  Granulocyte collection relies on the use of a red cell-sedimenting agent and is influenced by poorly defined intrinsic donor characteristics. The donor's baseline red cell (erythrocyte) sedimentation rate (ESR), a readily measurable intrinsic donor variable, may influence the effectiveness of red cell-sedimenting agents and affect the granulocyte yield.
  
  
  METHODS
  The in vitro and in vivo effects of 6-percent hydroxyethyl starch on the donor ESR were prospectively studied in 67 granulocytapheresis procedures with a blood cell separator, and the findings were correlated with granulocyte collection efficiency (GCE). A relationship that predicts the GCE on the basis of the donor ESR was then derived and tested.
  
  
  RESULTS
  The 3.7-fold mean increase in the donor ESR measured after in vitro addition of hydroxyethyl starch approximated the 3.3-fold increase measured when it was administered to the donors. Higher baseline ESR correlated with larger in vitro and in vivo hydroxyethyl starch-induced increases in ESR and predicted more efficient cell collections and greater cell yields. Furthermore, both ESR and GCE, which varied significantly among donors, remained constant for a given donor undergoing repeat procedures. The results could be summarized by a simple predictive formula that relates the GCE (%) to the ESR (mm/hour): GCE = 1.3ESR + 45. The GCE and yield as predicted by the formula were accurate within 10 percent of the observed values in six subsequent procedures.
  
  
  CONCLUSIONS
  In granulocyte harvests using a blood cell separator with hydroxyethyl starch as the sedimenting agent, 1) both ESR and GCE vary widely among donors yet may remain relatively constant for a given donor; 2) the baseline ESR correlates with hydroxyethyl starch-modified ESR and with GCE; and 3) it may be possible to predict GCE and yield from the donor's baseline ESR.
authors.affiliation: Department of Transfusion Medicine, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.forename: H G
authors.initials: HG
authors.lastname: Klein
mesh_terms: D001782:Blood Donors; D001799:Blood Sedimentation; D002498:Centrifugation; D006098:Granulocytes; D006801:Humans; D007937:Leukapheresis / Q000379:methods* / Q000706:statistics & numerical data; D007958:Leukocyte Count; D008433:Mathematics; D011446:Prospective Studies