title: A rest period does not affect in vitro storage properties in apheresis platelets collected from the buffy coat layer.
abstract: BACKGROUND
  A previous study demonstrated that several in vitro storage properties of apheresis platelets (PLTs) that are isolated by sedimentation against the collection container and subsequently resuspended can benefit from a rest period before continuous agitation. This study examines whether the in vitro storage properties of apheresis PLTs isolated by collection from the buffy coat layer benefit from a rest period before agitation.
  
  
  METHODS
  Freshly collected apheresis PLTs (Trima, GambroBCT) were divided into five 60-mL aliquots. One aliquot was immediately placed on a flat-bed agitator; the other aliquots were held on a laboratory bench for 1, 2, 4, and 6 hours before continuous agitation. Samples were obtained on Days 1, 5, and 7 for standard in vitro PLT assays. The experiment was repeated 12 times.
  
  
  RESULTS
  For each sampling day, no significant differences were observed in aliquots held with or without a rest period for any of the following PLT properties: PLT content, mean PLT volume, pH, pCO2, bicarbonate, glucose, lactate, hypotonic shock response, extent of shape change, aggregation, morphology, CD62P, CD63, and CD42b. Although regression analysis identified several in vitro properties whose mean levels appeared to improve with increasing length of the rest period, maximum differences in mean levels were small (<6%).
  
  
  CONCLUSIONS
  The in vitro storage properties of Trima apheresis PLTs isolated from the buffy coat layer do not benefit from a rest period.
authors.affiliation: American Red Cross Biomedical Services, Holland Laboratory, Rockville, Maryland 20855, USA. Steven.Wagner2@redcross.org
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Wagner
authors.forename: Shalini
authors.initials: S
authors.lastname: Seetharaman
authors.forename: James
authors.initials: J
authors.lastname: Kurtz
mesh_terms: D058621:Blood Buffy Coat / Q000166:cytology*; D001781:Blood Component Removal / Q000379:methods; D001792:Blood Platelets / Q000166:cytology* / Q000378:metabolism; D001793:Blood Preservation / Q000379:methods*; D006801:Humans; D010974:Platelet Aggregation; D017713:Platelet Transfusion; D010983:Plateletpheresis / Q000379:methods*; D013997:Time Factors