M45.AB Non-radiographic axial spondyloarthritis of multiple sites in spine

Billable ICD-10-CM code, FY2026.

Applies from M45 Ankylosing spondylitis

Applicable to

• Rheumatoid arthritis of spine

Excludes1 (never code together)

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

Excludes2 (not included here)

• Behçet's disease (M35.2)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 93 — Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders
• CMS-HCC V22: HCC 40 — Rheumatoid Arthritis and Inflammatory Connective Tissue Disease
• RxHCC V08: HCC 83 — Rheumatoid Arthritis and Other Inflammatory Polyarthropathy
• ESRD V24: HCC 40

MS-DRG index

Defines the logic of DRG(s) 545-547 in MDC 08.

Code annotations containing back-references to M45.AB

Back-references to M45

• Type 1 Excludes: G55 Nerve root and plexus compressions in diseases classified elsewhere ("nerve root compression (due to) (in) ankylosing spondylitis (M45.-)")
• Code First: J99 Respiratory disorders in diseases classified elsewhere ("ankylosing spondylitis (M45.-)")
• Type 1 Excludes: M05 Rheumatoid arthritis with rheumatoid factor ("rheumatoid arthritis of spine (M45.-)")

Diagnosis Index entries for M45.AB

• Spondyloarthritis › axial › non-radiographic › multiple sites

Nearby codes

• M45.A4 Non-radiographic axial spondyloarthritis of thoracic region
• M45.A5 Non-radiographic axial spondyloarthritis of thoracolumbar region
• M45.A6 Non-radiographic axial spondyloarthritis of lumbar region
• M45.A7 Non-radiographic axial spondyloarthritis of lumbosacral region
• M45.A8 Non-radiographic axial spondyloarthritis of sacral and sacrococcygeal region
• M45.AB Non-radiographic axial spondyloarthritis of multiple sites in spine (this code)