M45 — Ankylosing spondylitis
Is M45 billable?
No — M45 is a non-billable header code. M45 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 20 billable codes beneath M45.
Billable codes under this header
- M45.0Ankylosing spondylitis of multiple sites in spine
- M45.1Ankylosing spondylitis of occipito-atlanto-axial region
- M45.2Ankylosing spondylitis of cervical region
- M45.3Ankylosing spondylitis of cervicothoracic region
- M45.4Ankylosing spondylitis of thoracic region
- M45.5Ankylosing spondylitis of thoracolumbar region
- M45.6Ankylosing spondylitis lumbar region
- M45.7Ankylosing spondylitis of lumbosacral region
- M45.8Ankylosing spondylitis sacral and sacrococcygeal region
- M45.9Ankylosing spondylitis of unspecified sites in spine
- M45.A0Non-radiographic axial spondyloarthritis of unspecified sites in spine
- M45.A1Non-radiographic axial spondyloarthritis of occipito-atlanto-axial region
- M45.A2Non-radiographic axial spondyloarthritis of cervical region
- M45.A3Non-radiographic axial spondyloarthritis of cervicothoracic region
- M45.A4Non-radiographic axial spondyloarthritis of thoracic region
- M45.A5Non-radiographic axial spondyloarthritis of thoracolumbar region
- M45.A6Non-radiographic axial spondyloarthritis of lumbar region
- M45.A7Non-radiographic axial spondyloarthritis of lumbosacral region
- M45.A8Non-radiographic axial spondyloarthritis of sacral and sacrococcygeal region
- M45.ABNon-radiographic axial spondyloarthritis of multiple sites in spine
M45 at a glance
| Code | M45 |
|---|---|
| Description | Ankylosing spondylitis |
| Billable | No — header code |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Excludes1 — never code together
The conditions below can never be reported together with M45 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes2 — not included here
The conditions below are not part of M45, but a patient may have both at the same time. When documentation supports it, M45 and the excluded code may both be reported.
- Behçet's disease (M35.2)
Inclusion terms
Alternative wording in documentation that is classified to M45.
- Rheumatoid arthritis of spine
Excludes2 — not included here — inherited from Chapter 13
The conditions below are not part of M45, but a patient may have both at the same time. When documentation supports it, M45 and the excluded code may both be reported.
- arthropathic psoriasis (L40.5-)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- compartment syndrome (traumatic) (T79.A-)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
What codes fall under M45? (11)
- M45.0Ankylosing spondylitis of multiple sites in spine
- M45.1Ankylosing spondylitis of occipito-atlanto-axial region
- M45.2Ankylosing spondylitis of cervical region
- M45.3Ankylosing spondylitis of cervicothoracic region
- M45.4Ankylosing spondylitis of thoracic region
- M45.5Ankylosing spondylitis of thoracolumbar region
- M45.6Ankylosing spondylitis lumbar region
- M45.7Ankylosing spondylitis of lumbosacral region
- M45.8Ankylosing spondylitis sacral and sacrococcygeal region
- M45.9Ankylosing spondylitis of unspecified sites in spine
- M45.ANon-radiographic axial spondyloarthritisnot billable
How long has M45 existed?
M45 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.
Which codes are confused with M45?
ICD-10-CM declares these codes mutually exclusive with M45 — exactly one of each pair can be correct for a given encounter.