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Legionella Antigen Urine Culture (Qualitative)

Published: August 9, 2026Updated: August 16, 2026

This test detects the presence of *Legionella* bacteria in your urine, often used to diagnose Legionnaires’ disease or atypical pneumonia when other tests are inconclusive.

Quick summary

["Helps confirm infection with *Legionella* bacteria in urine, supporting diagnosis of serious respiratory illnesses."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
38394-3
Short code
Legionella Ur Cult
Synonyms
Legionella Ur Cult
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
organism-specific-culture
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test if you have symptoms like fever, cough, chest pain, or difficulty breathing—especially if you’ve traveled recently, live in a crowded or poorly ventilated space, or have a weakened immune system. It’s also used in cases where other tests (like blood cultures or serology) are unclear or negative.

How the Test Works

A small urine sample is collected and cultured in a lab to identify *Legionella* bacteria. If present, the bacteria grow over days, and the test can detect their presence through microscopic or biochemical methods.

Sample Collection

You’ll provide a midstream urine sample (clean-catch) or a sterile catheter sample, depending on your medical needs. The sample is sent to a lab where it’s processed to detect bacterial growth.

What to Expect After Testing

Results typically take 2–5 days. If *Legionella* is found, your provider will work with you to determine the best treatment, which often includes antibiotics like azithromycin or doxycycline.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Urine Legionella Culture

Frequently asked questions

How long does it take to get results?
Results are usually available within 2–5 business days, depending on lab processing times.
Can I take antibiotics before testing?
Yes, but inform your provider immediately if you’ve started antibiotics. They may need to adjust testing or treatment plans.
Is this test painful or uncomfortable?
No, the urine sample is collected like any other midstream urine test—no needles or invasive procedures are involved.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy