ICD-10-CM
ICD-10 code for Ankylosing spondylitis: M45.9
The closest CDC title for "Ankylosing spondylitis" is M45.9, Ankylosing spondylitis of unspecified sites in spine. M45.9 is a billable code.
Source: CDC ICD-10-CM FY2027 order file dated June 16, 2026. Publisher page
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Codes under M45, then other CDC titles that name ankylosing spondylitis of unspecified sites in spine
A header groups codes and is not billed. A billable code is one you can report.
- M45Ankylosing spondylitisHeader
- M45.0Ankylosing spondylitis of multiple sites in spineBillable
- M45.1Ankylosing spondylitis of occipito-atlanto-axial regionBillable
- M45.2Ankylosing spondylitis of cervical regionBillable
- M45.3Ankylosing spondylitis of cervicothoracic regionBillable
- M45.4Ankylosing spondylitis of thoracic regionBillable
- M45.5Ankylosing spondylitis of thoracolumbar regionBillable
- M45.6Ankylosing spondylitis lumbar regionBillable
- M45.7Ankylosing spondylitis of lumbosacral regionBillable
- M45.8Ankylosing spondylitis sacral and sacrococcygeal regionBillable
- M45.9Ankylosing spondylitis of unspecified sites in spineBillable
- M45.ANon-radiographic axial spondyloarthritisHeader
- M45.A0Non-radiographic axial spondyloarthritis of unspecified sites in spineBillable
- M45.A1Non-radiographic axial spondyloarthritis of occipito-atlanto-axial regionBillable
- M45.A2Non-radiographic axial spondyloarthritis of cervical regionBillable
- M45.A3Non-radiographic axial spondyloarthritis of cervicothoracic regionBillable
- M45.A4Non-radiographic axial spondyloarthritis of thoracic regionBillable
- M45.A5Non-radiographic axial spondyloarthritis of thoracolumbar regionBillable
- M45.A6Non-radiographic axial spondyloarthritis of lumbar regionBillable
- M45.A7Non-radiographic axial spondyloarthritis of lumbosacral regionBillable
- M45.A8Non-radiographic axial spondyloarthritis of sacral and sacrococcygeal regionBillable
- M45.ABNon-radiographic axial spondyloarthritis of multiple sites in spineBillable
Excludes1
Excludes1 means these codes are not reported together.
From M45. A note on a category applies to every code under it.
Excludes2
Excludes2 means the other condition can be reported with this one when both are documented.
From M45. A note on a category applies to every code under it.
Related conditions
Related pages
- M45.9 code detailsNotes, nearby codes, CMS-HCC group
- Category M45Every code under it
- Chapter 13Diseases of the musculoskeletal system
- ICD-10 codes by conditionA to Z
- Check a list of ICD-10 codes
- Denial code CO-11Diagnosis does not support the procedure
- Denial code CO-146Diagnosis invalid for the date of service
- HCPCS Level II code lookup
Questions
What is the ICD-10 code for Ankylosing spondylitis?
The closest CDC title for "Ankylosing spondylitis" is M45.9, Ankylosing spondylitis of unspecified sites in spine. M45.9 is a billable code.
Is M45.9 billable?
Yes. M45.9 is a billable code in the FY2027 ICD-10-CM file. Use a more specific code when the record documents one.
What documentation notes apply to M45.9?
The CDC tabular list gives 2 Excludes1 notes (not coded together), 1 Excludes2 note (may be coded together when both are documented) for M45.9 and the categories above it. They are listed on this page.
What chapter is M45.9 in?
Chapter 13. Diseases of the musculoskeletal system.
When do ICD-10-CM codes change?
Every October 1, with the new fiscal year file. Some years add April 1 updates. This page uses the FY2027 file, effective October 1, 2026.