Ordering Recommendation

Use for the rapid identification of L. pneumophila; sensitivity is dependent on patient population and specimen type. Molecular testing is generally preferred; refer to Legionella Species by Qualitative PCR (2010125).

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Pericardial fluid, respiratory, or tissue specimens.

Specimen Preparation

Fluid: Prepare two duplicate slides. OR transfer 1 mL fluid to a sterile container.
Tissue: Transfer tissue to a sterile container and place on gauze moistened with sterile non-bacteriostatic saline to prevent drying.

Storage/Transport Temperature

Refrigerated. OR frozen if transport occurs more than 48 hours after collection.

Unacceptable Conditions

Non-respiratory specimens. Specimens in preservatives or viral transport medium.


Specimen source preferred.


Fluid or Tissue: Ambient: 12 hours; Refrigerated: 48 hours; Frozen: 1 week
Slides: Ambient: 1 week; Refrigerated: 1 week; Frozen: 1 week


Direct Fluorescent Antibody Stain




1-2 days

Reference Interval


Interpretive Data

Compliance Category



A negative stain result does not exclude the possibility of infection. False-negative results may occur due to sampling errors or a low number of organisms in the specimen. DFA is not recommended for diagnosing Legionella pneumophila-caused infections. For diagnosing Legionella pneumophila-caused infections, refer to Legionella Species, Culture (ARUP test code 0060113), Legionella Species by Qualitative PCR (ARUP test code 2010125) for amplified DNA testing of respiratory specimens, or Legionella pneumophila Antigen, Urine (ARUP test code 0070322) for urine specimens.

Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
2004599 Legionella pneumophila DFA Source 31208-2
2004600 Legionella pneumophila DFA Result 588-4
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • L. pneumophilia DFA
  • Legionella Smear, DFA
Legionella pneumophila DFA