title: False-negative chest radiographs in emergency department diagnosis of pneumonia.
abstract: BACKGROUND
  Emergency department (ED) patients frequently undergo chest x-ray (CXR) to evaluate for pneumonia. The rate of false-negative CXR in patients with pneumonia is unclear.
  
  
  OBJECTIVE
  Identify patients admitted with pneumonia who were diagnosed by CT despite nondiagnostic CXR.
  
  
  METHODS
  Retrospective analysis of quality improvement data on adult ED patients admitted with pneumonia over 21 months. Primary outcome was percent of patients diagnosed by CT despite normal CXR. Patients were classified as CXR-diagnosed if they had CXR and no CT, or if antibiotics were ordered after CXR and before CT. CT-based diagnosis was indicated by administration of antibiotics only after CT was completed.
  
  
  RESULTS
  49 patients (11.4%) were diagnosed by CT (p<0.001). These patients were younger (p<0.001) and more often complained of chest pain (p<0.001).
  
  
  CONCLUSIONS
  Patients with pneumonia may present with normal or nondiagnostic CXR, although false negatives may be less common than previously reported.
authors.affiliation: Center for Health Equity Research and Promotion, Philadelphia Veterans Affairs Medical Center, Robert Wood Johnson Clinical Scholar, University of Pennsylvania, Fellow, Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, PA. Previous affiliation: Dept of Emergency Medicine, Alpert Medical School of Brown University.
authors.forename: Brandon C
authors.initials: BC
authors.lastname: Maughan
authors.affiliation: Department of Emergency Medicine, Alpert Medical School of Brown University, Providence, RI.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Asselin
authors.affiliation: Department of Emergency Medicine, University of Massachusetts Medical School, Worcester, MA. Previous affiliation: Dept of Emergency Medicine, Alpert Medical School of Brown University.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Carey
authors.affiliation: Department of Emergency Medicine, St Anne's Hospital, Fall River, MA. Previous affiliation: Dept of Emergency Medicine, Alpert Medical School of Brown University.
authors.forename: Andrew
authors.initials: A
authors.lastname: Sucov
authors.affiliation: Department of Emergency Medicine, Alpert Medical School of Brown University, Providence, RI.
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Valente
mesh_terms: D000368:Aged; D003951:Diagnostic Errors; D004632:Emergency Medical Services / Q000592:standards; D005188:False Negative Reactions; D005260:Female; D006786:Hospitals, Urban / Q000592:standards; D006801:Humans; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000000981:diagnostic imaging*; D058996:Quality Improvement; D013902:Radiography, Thoracic / Q000592:standards; D012189:Retrospective Studies; D012237:Rhode Island; D014057:Tomography, X-Ray Computed
keywords: chest radiograph; computed tomography; false negative; pneumonia