M45: Ankylosing spondylitis
Codes under M45 (Ankylosing spondylitis). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.
| Code | Description | Billable |
|---|---|---|
| M45.0 | Ankylosing spondylitis of multiple sites in spine | ✓ |
| M45.0 | Ankylosing spondylitis of multiple sites in spine | ✓ |
| M45.1 | Ankylosing spondylitis of occipito-atlanto-axial region | ✓ |
| M45.1 | Ankylosing spondylitis of occipito-atlanto-axial region | ✓ |
| M45.2 | Ankylosing spondylitis of cervical region | ✓ |
| M45.2 | Ankylosing spondylitis of cervical region | ✓ |
| M45.3 | Ankylosing spondylitis of cervicothoracic region | ✓ |
| M45.3 | Ankylosing spondylitis of cervicothoracic region | ✓ |
| M45.4 | Ankylosing spondylitis of thoracic region | ✓ |
| M45.4 | Ankylosing spondylitis of thoracic region | ✓ |
| M45.5 | Ankylosing spondylitis of thoracolumbar region | ✓ |
| M45.5 | Ankylosing spondylitis of thoracolumbar region | ✓ |
| M45.6 | Ankylosing spondylitis lumbar region | ✓ |
| M45.6 | Ankylosing spondylitis lumbar region | ✓ |
| M45.7 | Ankylosing spondylitis of lumbosacral region | ✓ |
| M45.7 | Ankylosing spondylitis of lumbosacral region | ✓ |
| M45.8 | Ankylosing spondylitis sacral and sacrococcygeal region | ✓ |
| M45.8 | Ankylosing spondylitis sacral and sacrococcygeal region | ✓ |
| M45.9 | Ankylosing spondylitis of unspecified sites in spine | ✓ |
| M45.9 | Ankylosing spondylitis of unspecified sites in spine | ✓ |
| M45.A | Non-radiographic axial spondyloarthritis | — |
| M45.A | Non-radiographic axial spondyloarthritis | — |
| M45.A0 | Non-radiographic axial spondyloarthritis of unspecified sites in spine | ✓ |
| M45.A0 | Non-radiographic axial spondyloarthritis of unspecified sites in spine | ✓ |
| M45.A1 | Non-radiographic axial spondyloarthritis of occipito-atlanto-axial region | ✓ |
| M45.A1 | Non-radiographic axial spondyloarthritis of occipito-atlanto-axial region | ✓ |
| M45.A2 | Non-radiographic axial spondyloarthritis of cervical region | ✓ |
| M45.A2 | Non-radiographic axial spondyloarthritis of cervical region | ✓ |
| M45.A3 | Non-radiographic axial spondyloarthritis of cervicothoracic region | ✓ |
| M45.A3 | Non-radiographic axial spondyloarthritis of cervicothoracic region | ✓ |
| M45.A4 | Non-radiographic axial spondyloarthritis of thoracic region | ✓ |
| M45.A4 | Non-radiographic axial spondyloarthritis of thoracic region | ✓ |
| M45.A5 | Non-radiographic axial spondyloarthritis of thoracolumbar region | ✓ |
| M45.A5 | Non-radiographic axial spondyloarthritis of thoracolumbar region | ✓ |
| M45.A6 | Non-radiographic axial spondyloarthritis of lumbar region | ✓ |
| M45.A6 | Non-radiographic axial spondyloarthritis of lumbar region | ✓ |
| M45.A7 | Non-radiographic axial spondyloarthritis of lumbosacral region | ✓ |
| M45.A7 | Non-radiographic axial spondyloarthritis of lumbosacral region | ✓ |
| M45.A8 | Non-radiographic axial spondyloarthritis of sacral and sacrococcygeal region | ✓ |
| M45.A8 | Non-radiographic axial spondyloarthritis of sacral and sacrococcygeal region | ✓ |
| M45.AB | Non-radiographic axial spondyloarthritis of multiple sites in spine | ✓ |
| M45.AB | Non-radiographic axial spondyloarthritis of multiple sites in spine | ✓ |
Frequently asked questions
What is ICD-10-CM code M45?
M45 is an ICD-10-CM category covering Ankylosing spondylitis. It contains 42 more specific diagnosis codes, 40 of which are billable.
Is M45 a billable code?
No — M45 is a category header and isn't billable on its own. Code to the highest level of specificity using one of its subcodes (for example M45.0 — Ankylosing spondylitis of multiple sites in spine). 40 of the 42 codes under M45 are billable.
What codes fall under M45?
M45 includes M45.0, M45.0, M45.1, M45.1, M45.2, plus 37 more. See the full list with descriptions and billable status above.
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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.
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