title: The 30 minute rule for red blood cells: in vitro quality assessment after repeated exposure to 30°C.
abstract: BACKGROUND
  Red blood cells (RBC) may be out of temperature control only for 30 minutes before they must be discarded, but evidence for this rule is weak. We investigated the effect on RBC quality of multiple exposures to 30°C.
  
  
  METHODS
  RBC units made after 24 hours of whole blood ambient hold were pooled and split into adult and pediatric units and exposed to permitted deviations (5-hr core temperature 10°C, 12-hr surface temperature 10°C). Test units were exposed to 30°C once, twice, or three times on each of Days 15, 17, and 21, for 30 or 60 minutes. Negative controls were not exposed to 30°C; positive control was exposed to 30°C for 24 hours.
  
  
  RESULTS
  Adult units exposed once for 30 or 60 minutes (×3 occasions) showed no more hemolysis than negative control. Units exposed to 30°C for two or three periods of 60 minutes showed more hemolysis from Day 28. Hemolysis in pediatric units exposed for 30 minutes (×3) was not increased but units exposed to one or two periods of 60 minutes (×3) showed higher hemolysis. No differences were seen in supernatant potassium. ATP remained at an acceptable level on Day 28 in all but positive controls.
  
  
  CONCLUSIONS
  There was no evidence of significant damage to RBC after exposure to 30°C for three periods of 30 minutes. Multiple exposures of 60 minutes caused limited damage but this was within current regulatory limits if there were three or fewer exposures, suggesting that a 60-minute rule may be feasible.
authors.affiliation: Components Development Laboratory, NHS Blood & Transplant, Brentwood, UK. stephen.thomas@nhsbt.nhs.uk
authors.forename: Stephen
authors.initials: S
authors.lastname: Thomas
authors.forename: Vicky
authors.initials: V
authors.lastname: Hancock
authors.forename: Rebecca
authors.initials: R
authors.lastname: Cardigan
mesh_terms: D019794:2,3-Diphosphoglycerate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D001771:Blood Banks / Q000592:standards*; D001793:Blood Preservation / Q000592:standards*; D001800:Blood Specimen Collection / Q000592:standards; D002470:Cell Survival; D015925:Cryopreservation / Q000592:standards; D017707:Erythrocyte Transfusion / Q000592:standards*; D004912:Erythrocytes / Q000166:cytology* / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism; D006400:Hematocrit; D006454:Hemoglobins; D006461:Hemolysis; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D017744:Medical Waste Disposal / Q000592:standards*; D011188:Potassium / Q000378:metabolism; D011786:Quality Control; D013696:Temperature; D013997:Time Factors
chemical_list: D006454:Hemoglobins; D017744:Medical Waste Disposal; D019794:2,3-Diphosphoglycerate; D019344:Lactic Acid; D000255:Adenosine Triphosphate; D005947:Glucose; D011188:Potassium