Rapid and sensitive method for quantitation of Legionella pneumophila serogroup 1 antigen from human urine

A reversed passive hemagglutination test was developed to assay relative concentrations of soluble antigen of Legionnaires disease (Legionella pneumophila serogroup 1) in human urine samples. The test is highly sensitive, being able to detect as little as 0.0002 microgram of total antigen. Preliminary results with this test on serial urine and serum samples from a patient with legionellosis show that measurable amounts of antigen are present in urine during the course of the illness. However, no antigen could be detected in the serum of the patient.