Legionnaires' disease

This code identifies a severe form of pneumonia caused by Legionella bacteria, often presenting with fever, cough, and shortness of breath. It can range from a mild flu-like illness (Pontiac fever) to a life-threatening lung infection. The bacteria are typically acquired by inhaling contaminated water droplets.

Assign this code when documentation explicitly states a diagnosis of Legionnaires' disease, confirmed by laboratory testing (e.g., urine antigen, culture, PCR). This code is appropriate for both community-acquired and healthcare-associated cases. Ensure the physician's final diagnosis supports this specific bacterial pneumonia.

• Do not use this code for Pontiac fever; a separate code exists for that milder form.
• Always look for documentation of the causative organism to support this specific diagnosis.
• Consider sequencing this code as the primary diagnosis when it is the reason for the encounter, followed by any associated complications.