Potential false-positive urine Legionella enzyme immunoassay test results

  • James ComoEmail author
  • Matthew A. Moffa
  • Nitin Bhanot
  • Zaw Min
  • Kelly Stefano Cole
  • James Kuzyck
  • Thomas L. Walsh
Original Article


The objective of this study was to identify potential false-positive urine Legionella pneumophila (Legionella) enzyme immunoassay test results. A total of 107 consecutive patients with positive EIA tests were retrospectively analyzed over a 34-month period. Concurrent blood, urine, and sputum cultures, as well as chest radiographic findings, were reviewed in these patients. Twenty patients (19%) had no radiographic evidence of pulmonary disease despite a positive EIA test. In those 20 patients, 14 also had growth of non-Legionella bacteria. Of patients with an infiltrate or opacity on chest imaging, only 27 had Legionella sputum cultures obtained, with Legionella culture growth occurring in 7 (26%). Nine other patients had negative Legionella sputum cultures but the growth of another pathogenic organism in blood, sputum, and/or urine cultures. Pseudomonas aeruginosa was the most common organism isolated, found in 20% of patients in the entire cohort. Twenty-five patients (23%) were characterized as having probable false-positive Legionella urinary antigen EIA testing, and an additional 17 patients (16%) were characterized as having possible false-positive Legionella EIA tests. Our findings suggest that urine Legionella EIA tests may lead to a substantial number of cases being misdiagnosed as Legionaries’ disease in patients with non-Legionella bacterial colonization or infection.


Legionella Enzyme immunoassay EIA Urine antigen testing Urine alone 



The authors would like to thank Lori Vandiver for assistance with electronic data capture.


  1. 1.
    McDade JE, Shepard CC, Fraser DW, Tsai TR, Redus MA, Dowdle WR, Laboratory Investigation Team (1977) Legionnaires’ disease: isolation of a bacterium and demonstration of its role in other respiratory disease. N Engl J Med 297(22):1197–1203CrossRefGoogle Scholar
  2. 2.
    Marston BJ, Plouffe JF, File TM Jr, Hackman BA, Salstrom SJ, Lipman HB, Kolczak MS, Breiman RF (1997) Incidence of community-acquired pneumonia requiring hospitalization. Results of a population-based active surveillance study in Ohio. Arch Intern Med 157(15):1709–1718CrossRefGoogle Scholar
  3. 3.
    Benin A, Benson R, Besser R (2002) Trends in legionnaires’ disease, 1980-1998: declining mortality and new patterns of diagnosis. Clin Infect Dis 35(9):1039–1046CrossRefGoogle Scholar
  4. 4.
    Tilon RC (1979) Legionnaires’ disease antigen detected by enzyme-linked immunosorbent assay. Ann Intern Med 90:697–698CrossRefGoogle Scholar
  5. 5.
    Kohler RB, Zimmerman SE, Wilson E, Allen SD, Edelstein H, Wheat LJ, White A (1981) Rapid immunoassay diagnosis of legionnaires’ disease: detection and partial characterization of urinary antigen. Ann Intern Med 94(5):601–605CrossRefGoogle Scholar
  6. 6.
    Product information, BINAX™ Legionella urinary antigen EIA. Accessed 30 April 2018
  7. 7.
    Shimada T, Noguchi Y, Jackson J, Miyashita J, Hayashino Y, Kamiya T, Yamazaki S, Matsumura T, Fukuhara S (2009) Systematic review and metaanalysis: urine antigen tests for legionellosis. Chest 136(6):1576–1585CrossRefGoogle Scholar
  8. 8.
    Deforge L, Legrand P, Tankovic J, Brun-Buisson C, Lang P, Soussy CJ (1999) Case of false-positive results of the urinary antigen test for Legionella pneumophila. Clin Infect Dis 29(4):953–954CrossRefGoogle Scholar
  9. 9.
    Bailleul E, Magerman A, Mewis V, Peeters V, Rummens JL, Cartuyvels R (2004) False positive result with BinaxNOW Legionella antigen immunochromatographic (ICT) assay: response to Helbig et al. J Med Microbiol 53(2):173CrossRefGoogle Scholar
  10. 10.
    Dominguez J, Manterola JM, Blavia R, Sopena N, Belda FJ, Padilla E, Gimenez M, Sabria M, Morera J, Ausina V (1996) Detection of Legionella pneumophila serogroup I antigen in nonconcentrated urine and urine concentrated by selective ultrafiltration. J Clin Microbiol 34(9):2334–2336Google Scholar
  11. 11.
    Beraud L, Gervasoni K, Freydiere AM, Descours G, Ranc AG, Vandenesch F, Lina G, Gaia V, Jarraud S (2015) Comparison of Sofia Legionella FIA and BinaxNOW urinary antigen card in two national reference centers. Eur J Clin Microbiol Infect Dis 34:1803–1807CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Medicine and Division of Infectious DiseasesAllegheny General HospitalPittsburghUSA
  2. 2.Department of Medicine and Division of Infectious DiseasesWest Penn HospitalPittsburghUSA
  3. 3.Department of Pathology, Clinical Microbiology LaboratoryAllegheny Health NetworkPittsburghUSA

Personalised recommendations