mrcem2-1821

A 42-year-old man presents with a high temperature, difficulty breathing, diarrhea and vomiting, fatigue, and fainting. He has recently returned from a wellness retreat in France. The patient is referred to the medical team on duty and admitted to the hospital. They suspect a potential diagnosis of Legionnaires’ disease.
What is the definitive test used to confirm a case of Legionnaires’ disease?