Legionella and community-acquired pneumonia: a review of current diagnostic tests from a clinician's viewpoint

Am J Med. 2001 Jan;110(1):41-8. doi: 10.1016/s0002-9343(00)00624-0.


Many physicians are unaware of the limitations of the available tests for diagnosing infections with Legionella organisms. Geographic differences in the importance of nonpneumophila Legionella species as pathogens are underrecognized, in part because available diagnostic tests are biased toward the detection of pneumophila serogroup 1. Routine laboratory practices reduce the likelihood of culturing Legionella species from clinical isolates. Failure of seroconversion is common, particularly with nonpneumophila species; even when seroconversion occurs, it may take much longer than 4 weeks. Urinary antigen testing has insufficient sensitivity to affect clinical management in most regions of the United States, as it can reliably detect only L. pneumophila serogroup 1 infections. Polymerase chain reaction-based techniques offer hope of providing highly sensitive, rapid diagnostic tests for all Legionella species, but limitations in the current tests will make validating them difficult.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Antigens, Bacterial / urine
  • Blood / microbiology
  • Community-Acquired Infections / diagnosis
  • Community-Acquired Infections / microbiology
  • Diagnosis, Differential
  • Fluorescent Antibody Technique, Direct
  • Humans
  • Legionella / genetics
  • Legionella / immunology
  • Legionella / isolation & purification*
  • Legionella pneumophila / isolation & purification
  • Legionellosis / diagnosis*
  • Legionellosis / microbiology
  • Legionnaires' Disease / diagnosis
  • Pneumonia, Bacterial / diagnosis*
  • Pneumonia, Bacterial / epidemiology
  • Pneumonia, Bacterial / microbiology*
  • Polymerase Chain Reaction*
  • Predictive Value of Tests
  • Sensitivity and Specificity
  • Sputum / microbiology
  • Time Factors
  • United States / epidemiology


  • Antigens, Bacterial