title: Regional and temporal variation in American Red Cross blood donations, 1995 to 2005.
abstract: BACKGROUND
  Maintaining a stable blood supply is a critical goal of the American Red Cross Blood Services. Extensive Red Cross data provided the opportunity to assess both long-term and short-term trends in the variation of weekly blood donations.
  
  
  METHODS
  Overall trends and week-to-week variation in donation rates were assessed in volunteer, whole-blood donations from 1995 to 2005 among three Red Cross donor regions: the Connecticut region, the Greater Chesapeake and Potomac (Maryland) region, and the Southern California region, adjusting for population change, calendar time, age, sex, and donor region.
  
  
  RESULTS
  Weekly donation rates varied widely by region, ranging from 3.5 donations per 10,000 persons in Southern California to 10.2 donations per 10,000 in Connecticut. Week-to-week variation in donation rates within each region was also quite high. Typical swings in weekly donation rates ranged from 38 percent in Connecticut to 56 percent in Southern California. Week-to-week variation was also 103 percent higher (95% confidence interval [CI], 87%-120%) among 18- to 24-year-old donors, compared to 25- to 44-year-olds, ranging from 32 to 49 percent. By comparison, week-to-week variation among adults 25 and older was more stable, ranging from 16 to 21 percent.
  
  
  CONCLUSIONS
  This study suggests that there is a great deal of variation in donation rates, particularly among the youngest donors. Improving recruitment and retention among these donors will be critical to maintaining an adequate blood supply as the donor population ages.
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
authors.forename: Stephen O
authors.initials: SO
authors.lastname: Crawford
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Reich
authors.forename: Ming-Wen
authors.initials: MW
authors.lastname: An
authors.forename: Ron
authors.initials: R
authors.lastname: Brookmeyer
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Louis
authors.forename: Kenrad E
authors.initials: KE
authors.lastname: Nelson
authors.forename: Edward P
authors.initials: EP
authors.lastname: Notari
authors.forename: Jonathan
authors.initials: J
authors.lastname: Trouern-Trend
authors.forename: Shimian
authors.initials: S
authors.lastname: Zou
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D001771:Blood Banks / Q000706:statistics & numerical data*; D001782:Blood Donors / Q000706:statistics & numerical data* / Q000600:supply & distribution*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012011:Red Cross; D017678:Sex Distribution; D013997:Time Factors; D014481:United States