Legionella urinary antigen assay for CAP in adults

Consider performing Legionella urinary antigen assays for adults with high-severity CAP who have risk factors for infection with Legionella species (eg chronic lung disease, smoking, diabetes, advanced kidney disease, cancer, immune compromise [including chronic corticosteroid use]).

Legionella urinary antigen assays that detect Legionella pneumophila serogroup 1 (the most prevalent type of L. pneumophila causing infection) are widely available. However, NAAT (eg PCR) is the preferred investigation for infection with Legionella species because it is more sensitive and convenient than urinary antigen assaysKawasaki, 2022Muyldermans, 2020. Paired serology can also be considered.

For a list of other clinical and microbiological investigations for CAP in adults, see Clinical and microbiological investigations for community-acquired pneumonia (CAP) in adults.