Legionellosis laboratory tests

Diagnosis
The most useful diagnostic tests detect the bacteria in sputum, find Legionella antigens in urine samples, or compare antibody levels to Legionella in two blood samples obtained 3 to 6 weeks apart. The urine antigen test is simple, quick, and very reliable; however it will only detect Legionella pneumophila serogroup #1. Also the urine antigen test will not identify the specific subtyping so it cannot be used to match the patient with the environmental source of infection.