2026 ICD-10-CM Diagnosis Code M08.1Juvenile ankylosing spondylitis
ICD-10-CM Codes›M00–M99›M05-M14›M08
- Billable — Valid for Submission
- Chronic Condition
M08.1 is a billable ICD-10-CM diagnosis code for juvenile ankylosing spondylitis. 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. Coders also document this condition as ankylosing spondylitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Juvenile arthritis and Spondylopathies/spondyloarthropathy (including infective).
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Ankylosing spondylitis
- Ankylosing spondylitis with multisystem involvement
- Ankylosing spondylitis with organ / system involvement
- Juvenile ankylosing spondylitis
- Juvenile spondyloarthropathy
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Type 1 Excludes
- ankylosing spondylitis in adults M45.0
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Spondylitis (chronic) - See Also: Spondylopathy, inflammatory;
- ankylosing (chronic) - M45.9
- juvenile - M08.1
- juvenile ankylosing (chronic) - M08.1
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Spondylitis(chronic)
- ankylosing (chronic)
- juvenile
- Spondylitis(chronic)
- juvenile ankylosing (chronic)
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Ankylosing Spondylitis
Ankylosing spondylitis (AS) is a type of arthritis of the spine. It causes inflammation (swelling) between your vertebrae (the bones that make up your spine) and the joints between your spine and pelvis. AS inflammation can cause stiffness and make it difficult to move and bend.
The full article covers:
- What is ankylosing spondylitis?
- Who is more likely to get ankylosing spondylitis?
- What causes ankylosing spondylitis?
- What are the symptoms of ankylosing spondylitis?
- How is ankylosing spondylitis diagnosed?
- What are the treatments for ankylosing spondylitis?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M08.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M08.1Overview
Is M08.1 (Juvenile arthritis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report juvenile ankylosing spondylitis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does M08.1 group to?
When juvenile ankylosing spondylitis 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.
What is the ICD-9 equivalent of M08.1?
Under the General Equivalence Mappings, juvenile ankylosing spondylitis converts to ICD-9-CM 720.0 (ankylosing spondylitis). 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.
