title: Validity of calendar day-based definitions for community-onset bloodstream infections.
abstract: BACKGROUND
  Community-onset (CO) bloodstream infections (BSI) are those BSI where the blood culture is drawn <48 hours from hospital admission. However, exact times of culture draw or hospital admission are not always available. We evaluated the validity of using 2- or 3- calendar day based definitions for CO-BSI by comparing to a "gold standard" 48-hour definition.
  
  
  RESULTS
  Among the population-based cohort of 14,106 episodes of BSI studied, 10,543 were classified as CO based on "gold standard" 48-hour criteria. When 2-day and 3-day definitions were applied, 10,396 and 10,707 CO-BSI episodes were ascertained, respectively. All but 147 (1.4%) true CO-BSI cases were included by using the 2-day definition. When the 3-day definition was applied, all cases of CO-BSI were identified but and additional 164 (1.5%) cases of hospital-onset HO-BSI were also included. Thus the sensitivity and specificity of the 2-day definition was 98.6% and 100% and for the 3-day definition was 100% and 98.5%, respectively. Overall, only 311 (2.2%) cases were potentially miss-classifiable using either the 2- or 3-calendar day based definitions.
  
  
  CONCLUSIONS
  Use of either a 2- or 3-day definition is highly accurate for classifying CO-BSI.
authors.affiliation: Department of Medicine, Royal Inland Hospital, 311 Columbia Street, Kamloops, BC, V2C 2T1, Canada. klaupland@gmail.com.|Department of Medicine, University of Calgary, Calgary, AB, Canada. klaupland@gmail.com.|Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada. klaupland@gmail.com.
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Laupland
authors.affiliation: Department of Medicine, University of Calgary, Calgary, AB, Canada. dan.gregson@cls.ab.ca.|Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada. dan.gregson@cls.ab.ca.|Division of Microbiology, Calgary Laboratory Services, #9, 3535 Research Road NW, Calgary, AB, T2A 2K8, Canada. dan.gregson@cls.ab.ca.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Gregson
authors.affiliation: Department of Medicine, University of Calgary, Calgary, AB, Canada. deirdre.church@cls.ab.ca.|Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada. deirdre.church@cls.ab.ca.|Division of Microbiology, Calgary Laboratory Services, #9, 3535 Research Road NW, Calgary, AB, T2A 2K8, Canada. deirdre.church@cls.ab.ca.
authors.forename: Deirdre L
authors.initials: DL
authors.lastname: Church
mesh_terms: D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000175:diagnosis*; D006801:Humans; D010343:Patient Admission; D018805:Sepsis / Q000175:diagnosis*