A48.1 Legionnaires' disease

Billable ICD-10-CM code, FY2026. Acts as a Major Complication or Comorbidity (MCC) as a secondary diagnosis.

Applies from A48 Other bacterial diseases, not elsewhere classified

Excludes1 (never code together)

• actinomycetoma (B47.1)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 282 — Aspiration and Specified Bacterial Pneumonias
• CMS-HCC V22: HCC 114 — Aspiration and Specified Bacterial Pneumonias
• ESRD V24: HCC 114

MS-DRG index

Defines the logic of DRG(s) 177-179 in MDC 04.

Approximate ICD-9-CM (GEMs)

• 482.84 Pneumonia due to Legionnaires' disease

Code annotations containing back-references to A48.1

Back-references to A48.1

• Type 1 Excludes: J15 Bacterial pneumonia, not elsewhere classified ("Legionnaires' disease (A48.1)")

Diagnosis Index entries for A48.1

• Disease, diseased › legionnaires'
• Infection, infected, infective (opportunistic) › Legionella pneumophila
• Legionellosis
• Legionnaires' › disease
• Legionnaires' › pneumonia

Nearby codes

• A48 Other bacterial diseases, not elsewhere classified
• A48.0 Gas gangrene
• A48.1 Legionnaires' disease (this code)
• A48.2 Nonpneumonic Legionnaires' disease [Pontiac fever]
• A48.3 Toxic shock syndrome
• A48.4 Brazilian purpuric fever
• A48.5 Other specified botulism
• A48.51 Infant botulism