title: Best Clinical Practice: Blood Culture Utility in the Emergency Department.
abstract: BACKGROUND
  Bacteremia affects 200,000 patients per year, with the potential for significant morbidity and mortality. Blood cultures are considered the most sensitive method for detecting bacteremia and are commonly obtained in patients with fever, chills, leukocytosis, focal infections, and sepsis.
  
  
  OBJECTIVE
  We sought to provide emergency physicians with a review of the literature concerning blood cultures in the emergency department.
  
  
  CONCLUSIONS
  The utility of blood cultures has been a focus of controversy, prompting research evaluating effects on patient management. Bacteremia is associated with increased mortality, and blood cultures are often obtained for suspected infection. False-positive blood cultures are associated with harm, including increased duration of stay and cost. This review suggests that blood cultures are not recommended for patients with cellulitis, simple pyelonephritis, and community-acquired pneumonia, because the chance of a false-positive culture is greater than the prevalence of true positive cultures. Blood cultures are recommended for patients with sepsis, meningitis, complicated pyelonephritis, endocarditis, and health care-associated pneumonia. Clinical prediction rules that predict true positive cultures may prove useful. The clinical picture should take precedence. If cultures are obtained, two bottles of ≥7 mL should be obtained from separate peripheral sites.
  
  
  CONCLUSIONS
  Blood cultures are commonly obtained but demonstrate low yield in cellulitis, simple pyelonephritis, and community-acquired pneumonia. The Shapiro decision rule for predicting true bacteremia does show promise, but clinical gestalt should take precedence. To maximize utility, blood cultures should be obtained before antibiotic therapy begins. At least two blood cultures should be obtained from separate peripheral sites.
authors.affiliation: Department of Emergency Medicine, San Antonio Military Medical Center, Fort Sam Houston, Texas.
authors.forename: Brit
authors.initials: B
authors.lastname: Long
authors.affiliation: Department of Emergency Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Alex
authors.initials: A
authors.lastname: Koyfman
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D016470:Bacteremia / Q000175:diagnosis*; D000071997:Blood Culture / Q000706:statistics & numerical data*; D002481:Cellulitis / Q000175:diagnosis / Q000188:drug therapy; D004636:Emergency Service, Hospital / Q000458:organization & administration; D006801:Humans; D011014:Pneumonia / Q000175:diagnosis / Q000188:drug therapy; D011704:Pyelonephritis / Q000175:diagnosis / Q000188:drug therapy; D012196:Review Literature as Topic; D018805:Sepsis / Q000175:diagnosis / Q000188:drug therapy
chemical_list: D000900:Anti-Bacterial Agents
keywords: bacteremia; blood cultures; blood stream infection; cellulitis; pneumonia; pyelonephritis; sepsis