C4Legio LFA

Legionnaires’ disease

Legionella Pneumophila in lugs, 3D

Human lungs infected by Legionella pneumophila

What’s Legionnaires’ disease ?

Legionnaires’ disease is a severe pneumonia caused by bacteria of the genus Legionella. One usually gets it by breathing in mist from water that contains the bacteria. The mist may come from hot tubs, showers or air-conditioning units for large buildings.

Symptoms of Legionnaires’ disease include high fever, chills, a cough and sometimes muscle aches and headaches. But other types of pneumonia have similar symptoms. So, lab tests are required to detect the specific bacteria that causes Legionnaires’ disease.

Key figures about Legionellosis

Up to


mortality rate (1)

From 20 to


of cases stay non-diagnosed (3)

More than

cases in Europe in 2018 / + 28% versus 2017 (1)

7000 in the US in 2018 (2)

Increase of


of cases' number in Europe between 2017 and 2018 (1)

What’s the standard of care today ?

Currently, there are two types of tests for Legionnaires’ disease diagnosis :

Culture-based tests (gold standard)
This test has a 5 to 15 days turn -around-time (TAT), detects all serogroups, but is operator and lab-dependent. As a results, sensitivity ranges from 20 to 80%.

Urinary antigens tests

This test has a short TAT (20 minutes), but detects reliably only serogroup 1 (there are 14 serogroups of Legionella). Serogroup 1 is the most common (50 to 80% of cases), but all are deadly.

Combining rapid and accurate diagnosis is game-changing: mortality rate is < 10% for patients treated within 48h, while it ramps up to almost 50% for patients treated 48 hours after the first signs of infection.

Patient Care, a priority at C4Diagnostics
Patient Care, a priority at C4Diagnostics

What are the main features of C4Legio LFA diagnostic test ? 

C4Legio LFA (lateral flow assay), the test developed by C4Diagnostics to detect Legionnaires’ disease answers the above-mentioned limitations and enables :

  • detection of all serogroups of Legionella
  • turn-around time of 48 hours

The first version of the test was a Research Use Only version (C4Legio). In 2021, we have moved to a second version using the lateral flow assay (C4Legio LFA).

Relevant publications