Legionella antigen, urine-2389

Test info

Legionella antigen, urine

Qualitative detection of Legionella pneumophila serogroup 1 antigen in the urine of patients with symptoms of pneumonia.



Due to only 40% sensitivity in patients with mild pneumonia, this test is not recommended for outpatients.


Urine, random
10 mL
4.0 mL

Transfer specimen to a Urine preservative vial/tube, C&S prior to transport

Processing urine specimens with BD Vacutainer collection products


Screw cap plastic container (sterile)


Refrigerated (preferred) - 14 days

Ambient - 24 hours

  • Improper label (unlabeled or mislabeled)
  • Time delay between time of collection and receipt of specimen
  • Improper transport container
  • Improper transport temperature
    • Specimen at room temperature for longer than 24 hours
    • Urine refrigerated longer than 14 days
  • Inappropriate specimen type
    • Specimens other than urine
  • Leaking container


AHL - Microbiology: M
Routine - 1 day
STAT - 1 hour

Rapid Immunochromatographic Assay

Clinical and Interpretive info


Negative for L. pneumophila serogroup 1 antigen, suggesting no recent or current infection.



Legionnaires' disease is caused by Legionella pneumophila and is characterized as an acute febrile respiratory illness ranging in severity from mild illness to fatal pneumonia.  The mortality rate, ranging from 25%-40%, can be lowered if the disease is diagnosed rapidly and appropriate antimicrobial therapy is instituted early. 

Known risk factors for contracting Legionella pneumophila include immunosuppression, cigarette smoking, alcohol consumption and concomitant pulmonary disease. Contaminated, aerosolized water systems are a major source of disease. The young and the elderly are particularly susceptible.  Legionella pneumophila is responsible for 80%-90% of reported cases of Legionella infection with serogroup 1 accounting for greater than 70% of all legionellosis. 

Current methods for laboratory detection of pneumonia caused by Legionella pneumophila require a respiratory specimen (sputum, bronchial washing, etc.).  Unfortunately, one of the presenting signs of patients with Legionnaires' disease is the relative lack of productive sputum.  The Binax NOW Legionella Urinary Antigen Test allows for early diagnosis of Legionella pneumophila serogroup 1 infection through the detection of a specific soluble antigen present in the urine of infected patients.  Legionella pneumophila serogroup 1 antigen has been detected in urine as early as three days after the onset of symptoms and persists for up to one year.

Sensitivity of the urine antigen test varies with the severity of the pneumonia. In patients with severe pneumonia requiring intensive care and ventilator assistance, the Binax NOW Legionella Urinary Antigen Test has a sensitivity of 95%. In patients with moderately severe pneumonia, sensitivity is 81%. In outpatients and patients with mild pneumonia, the sensitivity of the urine antigen test is only 40%. Specificity of the Binax NOW Legionella Urinary Antigen test is 95%. It is intended, in conjunction with culture and other methods, to aid in the presumptive diagnosis of Legionella infection (Legionnaires' disease).