What is analysed?

Legionella is a bacteria found in natural water sources (such as lakes) and man-made water systems (such as hot tubs and air conditioning) that can cause a severe form of pneumonia called Legionnaires' disease.

The Legionella test is used to detect the presence of Legionella bacteria, specifically Legionella pneumophila.

What does the result mean?

The result indicates the presence or absence of Legionella bacteria in a collected sample. A positive result suggests an active Legionnaires’ disease infection.

Why conduct the analysis?

The Legionella test is conducted to identify Legionella bacteria in order to help diagnose Legionnaires’ disease. In addition, the analysis may also be conducted to guide antibiotic treatment.

When to conduct the analysis?

The Legionella test is conducted when symptoms of Legionnaires’ disease, such as a high fever, shortness of breath, chest pain, and a cough are observed.

What sample is required?

A urine sample is generally required.

Further tests may require:

• A blood sample, usually drawn from a vein in the arm
• A sample of sputum or lung tissue

Is any prior preparation necessary?

The type of prior preparation required depends on the type of sample being collected.

• For a urine sample: Patients can eat and drink before the sample is taken, but should avoid any medications or substances that could affect results.
• For a blood sample: Patients should fast for 8-12 hours before the sample is taken.
• For a sample of sputum or lung tissue: Patients should drink plenty of fluids the evening before, and take the sample first thing in the morning before drinking anything or having breakfast.

How is it performed?

The collected sample is sent to a laboratory test, where it is analysed using:

• Urinary antigen techniques to detect Legionella antigens in the urine.
• Molecular methods to detect Legionella DNA through polymerase chain reactions
• Bacterial culture, which involves deliberately growing bacteria on a special container for a more detailed bacterial analysis later on.

What are the normal values?

A negative test result indicates that no Legionella bacteria was detected.

What does having altered values mean?

• Positive result: A positive test result indicates the presence of Legionella bacteria or antigens, suggesting an active Legionnaires' disease infection.