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M45 ICD-10-CM Code: Ankylosing spondylitis

A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.

Official description

M45

Ankylosing spondylitis

ICD-10-CM diagnosis code · United States clinical modification

Where M45 sits

  1. 1

    Chapter 13

    Diseases of the musculoskeletal system and connective tissue (M00-M99)

  2. 2

    Section

    Spondylopathies (M45-M49)

  3. 3

    Category M45

    Ankylosing spondylitis

  4. 4

    Code M45

    Ankylosing spondylitis

Codes under M45

M45 is a non-billable category. Choose the child code that best matches the documented diagnosis.

M45.0Ankylosing spondylitis of multiple sites in spineM45.1Ankylosing spondylitis of occipito-atlanto-axial regionM45.2Ankylosing spondylitis of cervical regionM45.3Ankylosing spondylitis of cervicothoracic regionM45.4Ankylosing spondylitis of thoracic regionM45.5Ankylosing spondylitis of thoracolumbar regionM45.6Ankylosing spondylitis lumbar regionM45.7Ankylosing spondylitis of lumbosacral regionM45.8Ankylosing spondylitis sacral and sacrococcygeal regionM45.9Ankylosing spondylitis of unspecified sites in spineM45.ANon-radiographic axial spondyloarthritis

Notes for this code

Inclusion terms

  • Rheumatoid arthritis of spine

Code first

No “code first” instruction is listed for M45.

Use additional code

No “use additional code” instruction is listed for M45.

Excludes1

Conditions that should not be reported together with this code.

  • arthropathy in Reiter's disease (M02.3-)
  • juvenile (ankylosing) spondylitis (M08.1)

Excludes2

Conditions not included here that may be reported separately when present.

  • Behçet's disease (M35.2)

Source and release

Data release
U.S. ICD-10-CM · FY 2027
Effective date
Oct 1, 2026

This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.

Review the CDC/NCHS ICD-10-CM source

Frequently asked questions

What does ICD-10-CM code M45 mean?

M45 is the FY 2027 U.S. ICD-10-CM code for “Ankylosing spondylitis.”

Is M45 a billable or specific ICD-10-CM code?

No. M45 has more specific child codes in the FY 2027 reference data. Select the code that matches the documentation and confirm the active code set and payer requirements.

Where is M45 located in ICD-10-CM?

M45 is listed in Chapter 13, Diseases of the musculoskeletal system and connective tissue (M00-M99), within Spondylopathies (M45-M49) (M45–M49), under category M45, Ankylosing spondylitis.

What coding notes are listed for M45?

Its listed inclusion terms are Rheumatoid arthritis of spine. No code-first instruction is listed. Excludes1 notes: arthropathy in Reiter's disease (M02.3-); juvenile (ankylosing) spondylitis (M08.1). Excludes2 notes: Behçet's disease (M35.2).