2026 ICD-10-CM Diagnosis Code M06.1Adult-onset Still's disease

ICD-10-CM Codes›M00–M99›M05-M14›M06

ICD-10-CM M06.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M06.1 is a billable ICD-10-CM diagnosis code for adult-onset Still's disease. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 545 through 547. The code is restricted by the Medicare Code Editor to adult patients (age 15 through 124). Coders also document this condition as adult onset Still's disease. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Rheumatoid arthritis and related disease.

Code Identity

ICD-10-CM Code
M06.1
Billable Status
Yes — Valid for Submission
Code Describes
Adult-onset Still's disease
Short Description
Adult-onset Still's disease
Same as the full description in the CMS dataset.
Parent Code
M06
Other rheumatoid arthritis

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM05-M14Inflammatory polyarthropathies
CategoryM06Other rheumatoid arthritis
This CodeM06.1Adult-onset Still's disease

Code EditsBilling

Medicare Code Editor checks that affect claim validity for M06.1.

Adult diagnoses
The Medicare Code Editor detects inconsistencies in adult cases by checking a patient's age and any diagnosis on the patient's record. The adult code edits apply to patients age range is 15–124 years inclusive (e.g., senile delirium, mature cataract).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Adult onset Still's disease
  • Complex multigenic autoinflammatory syndrome

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Type 1 Excludes

  • Still's disease NOS M08.2

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

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

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MUS003
Rheumatoid arthritis and related disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Juvenile Arthritis

Juvenile arthritis (JA) is arthritis that happens in children. It causes joint inflammation (swelling), pain, stiffness, and loss of motion. Joints are places where two bones meet, such as your elbow or knee. It can affect any joint, but it is more common in the knees, hands, and feet.

The full article covers:

  • What is juvenile arthritis?
  • Who is more likely to get juvenile arthritis?
  • What causes juvenile arthritis?
  • What are the symptoms of juvenile arthritis?
  • How is juvenile arthritis diagnosed?
  • What are the treatments for juvenile arthritis?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert M06.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
714.2 Syst rheum arthritis NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About M06.1Overview

Is M06.1 (Other rheumatoid arthritis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report adult-onset Still's disease on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M06.1 group to?

When adult-onset Still's disease is the principal diagnosis on an inpatient stay, it groups to MS-DRG 545, 546, 547, with relative weights from 0.8362 to 2.4817 depending on complications. Higher weights mean higher Medicare reimbursement.

Who can M06.1 be reported for?

The Medicare Code Editor checks adult-onset Still's disease against patient demographics: this code is intended for adult patients (age 15 through 124). Claims outside these limits are flagged as inconsistent.

What is the ICD-9 equivalent of M06.1?

Under the General Equivalence Mappings, adult-onset Still's disease converts to ICD-9-CM 714.2 (syst rheum arthritis NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.