Inter-observer variation in the interpretation of chest radiographs for pneumonia in community-acquired lower respiratory tract infections

Clin Radiol. 2004 Aug;59(8):743-52. doi: 10.1016/j.crad.2004.01.011.


Aim: To assess inter-observer variation in the interpretation of chest radiographs of individuals with pneumonia versus those without pneumonia.

Materials and methods: Chest radiographs of out-patients with a lower respiratory tract infection (LRTI) were assessed for the presence of infiltrates by radiologists from three local hospitals and were reassessed by one university hospital radiologist. Various measures of inter-observer agreement were calculated.

Results: The observed proportional agreement was 218 in 243 patients (89.7%). Kappa was 0.53 (moderate agreement) with a 95% confidence interval of 0.37 to 0.69. The observed positive agreement (59%) was much lower than for negative agreement (94%). Kappa was considerably lower, if chronic obstructive pulmonary disease was present (kappa = 0.20) or Streptococcus pneumoniae (kappa = -0.29) was the infective agent.

Conclusion: The overall inter-observer agreement adjusted for chance was moderate. Inter-observer agreement in cases with pneumonia was much worse than the agreement in negative (i.e. non-pneumonia) cases. A general practitioner's selection of patients with a higher chance of having pneumonia for chest radiography would thus not improve the observer agreement.

Publication types

  • Multicenter Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Community-Acquired Infections / diagnostic imaging
  • Female
  • Humans
  • Lung / diagnostic imaging*
  • Male
  • Middle Aged
  • Observer Variation
  • Pneumonia / diagnostic imaging*
  • Prospective Studies
  • Radiography
  • Respiratory Tract Infections / diagnostic imaging*