Legionella pneumophila, DFA

CPT: 87278
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Test Details


  • Legionella Antigen
  • FA Smear for Legionella pneumophila


Determine the presence of Legionella pneumophila organisms in direct FA smear of specimen, providing rapid diagnosis


Test does not include Legionella species other than L pneumophila.


Direct fluorescent antibody (DFA)

Reference Interval

No Legionella pneumophila detected

Additional Information

Community-acquired and nosocomial infections caused by multiple serogroups of Legionella are increasingly recognized. Although culture is now possible on buffered charcoal yeast extract agar, the demonstration of organisms in tissue or brushings is the fastest way to make the diagnosis. It also has the advantage of applicability to specimens contaminated with other bacteria. Development of monoclonal antibodies have increased sensitivity and specificity. False-positive reaction has been reported in a case of pleuropulmonary tularemia and in cases of Campylobacter infection.

Specimen Requirements


Lung biopsy, lung exudate, pleural fluid, transtracheal aspirate, sputum, bronchial washing


1 mL lung exudate or 1 cc lung biopsy


Sterile leakproof container or slides


Contamination with normal flora from skin or other body surfaces should be avoided.

Storage Instructions

Refrigerate. Maintain specimen at 2°C to 8°C, and transport to the laboratory within 24 hours of collection.

Causes for Rejection

Swab specimen; inappropriate specimen transport device; improper labeling; specimen received after prolonged delay (usually more than 72 hours)

Clinical Information


Andersen LP, Bangsborg J. Crossreactions between Legionella and Campylobacter spp.Lancet. 1992 Jul 25; 340(8813):245. 1353168
Edelstein PH, Beer KB, Sturge JC, Watson AJ, Goldstein LC. Clinical utility of a monoclonal direct fluorescent reagent specific for Legionella pneumophila: Comparative study with other reagents. J Clin Microbiol. 1985 Sep; 22(3):419-421. 3900129
Friedman H, Wider R, Klein T. Immunodiagnostic assays for Legionellosis. Lab Management. 1983; 21:19-23.
Hart CA, Makin T. Legionella in hospitals: A review. J Hosp Infect. 1991 Jun; 18(Suppl A): 481-489. 1679819
Hicklin MD, Thomason BM, Chandler FW, Blackmon JA. Pathogenesis of acute Legionnaires' disease pneumonia. Am J Clin Pathol. 1980 Apr; 73(4):480-487. 6989229
Roy TM, Fleming D, Anderson WH. Tularemic pneumonia mimicking Legionnaires' disease with false-positive direct fluorescent antibody stains for Legionella.South Med J. 1989 Nov; 82(11):1429-1431. 2683131


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
085506 Legionella pneumophila DFA 588-4 085506 Legionella pneumophila DFA 588-4

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