Is legionnaires' disease easy to diagnose?

No: Presentation includes respiratory symptoms such as cough (may not be productive) and sob, fever, chills, and chest pain. Other symptoms include headache, nausea, vomiting, abdominal pain, or diarrhea. May also be characterized by a fever with a pulse-temperature dissociation, nonproductive cough, few pulmonary symptoms, diarrhea, hyponatremia, and elevated AST and alt.

Yes: The legionella urine antigen test has revolutionized the lab diagnosis of legionaires' disease. This test is 90% sensitive for l. Pneumophilia serogroup 1. Since 90% of community acquired legionella is serogroup 1 this makes the test 70-80% sensitive for making the diagnosis.