M06.1 Adult-onset Still's disease

Billable ICD-10-CM code, FY2026.

Excludes1 (never code together)

• Still's disease NOS (M08.2-)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 93 — Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders
• CMS-HCC V22: HCC 40 — Rheumatoid Arthritis and Inflammatory Connective Tissue Disease
• RxHCC V08: HCC 83 — Rheumatoid Arthritis and Other Inflammatory Polyarthropathy
• ESRD V24: HCC 40

MS-DRG index

Defines the logic of DRG(s) 545-547 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 714.2 Other rheumatoid arthritis with visceral or systemic involvement (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Adult diagnoses (age 15 through 124): Age conflict edit. These diagnoses are clinically expected only in patients age 15 through 124.

Code annotations containing back-references to M06.1

Back-references to M06.1

• Type 1 Excludes: M08.2 Juvenile rheumatoid arthritis with systemic onset ("adult-onset Still's disease (M06.1-)")

Diagnosis Index entries for M06.1

• Still's disease or syndrome (juvenile) › adult-onset

Nearby codes

• M06.072 Rheumatoid arthritis without rheumatoid factor, left ankle and foot
• M06.079 Rheumatoid arthritis without rheumatoid factor, unspecified ankle and foot
• M06.08 Rheumatoid arthritis without rheumatoid factor, vertebrae
• M06.09 Rheumatoid arthritis without rheumatoid factor, multiple sites
• M06.0A Rheumatoid arthritis without rheumatoid factor, other specified site
• M06.1 Adult-onset Still's disease (this code)
• M06.2 Rheumatoid bursitis
• M06.20 Rheumatoid bursitis, unspecified site
• M06.21 Rheumatoid bursitis, shoulder
• M06.211 Rheumatoid bursitis, right shoulder
• M06.212 Rheumatoid bursitis, left shoulder