Skip to main content

M45.A0 ICD-10-CM Code: Non-radiographic axial spondyloarthritis of unspecified sites in spine

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Inpatient Payment Groups (MS-DRG)

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0, Appendix B.

  • MS-DRG 545 — CONNECTIVE TISSUE DISORDERS WITH MCC (MDC 08)
  • MS-DRG 546 — CONNECTIVE TISSUE DISORDERS WITH CC (MDC 08)
  • MS-DRG 547 — CONNECTIVE TISSUE DISORDERS WITHOUT CC/MCC (MDC 08)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

  • HCC 93 — Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders (supersedes HCC 94)

Other models: CMS-HCC V22 HCC 40 · RxHCC V08 HCC 83

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Official Registry Overview & Definition

Non-radiographic axial spondyloarthritis of unspecified sites in spine is a billable ICD-10-CM diagnosis code (M45.A0).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for M45.A0 in the official ICD-10-CM tabular list.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Indexed Clinical Terms (1)

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.

  • Spondyloarthritis, axial, non-radiographic

Frequently Compared Codes

The official Excludes notes on M45.A0 name these codes. Each comparison page covers when the two can — or must not — be reported together.

Change history

  • FY2022 — 2021-10-01
    Added to the code set
    Non-radiographic axial spondyloarthritis of unspecified sites in spine
    FY2022 changes

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim.

Relationships & Classification

Official ICD-10-CM tabular notes on other codes that name M45.A0 or its code family.

2 Excludes1 notes across 2 chapters: G55 (via M45.-), M05 (via M45.-).

1 Code First instructions: J99 (via M45.-).

Potential MS-DRG Relationships (FY2026)

Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.

Named in the grouper logic of 3 MS-DRGs: DRG 545 (MDC 08), DRG 546 (MDC 08), DRG 547 (MDC 08).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):MUS011 — Spondylopathies/spondyloarthropathy (including infective) (default); MUS003 — Rheumatoid arthritis and related disease.

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Contextual Map

Every relationship of M45.A0 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

  • M00-M99 — Chapter 13: Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) (M00-M99) [Hierarchy]
  • M45-M49 — Spondylopathies [Hierarchy]

Referenced by Excludes1 notes

  • G55 — Nerve root and plexus compressions in diseases classified elsewhere [Excludes1](via M45.-): “nerve root compression (due to) (in) ankylosing spondylitis (M45.-)” · check together
  • M05 — Rheumatoid arthritis with rheumatoid factor [Excludes1](via M45.-): “rheumatoid arthritis of spine (M45.-)” · check together

Referenced by Code First instructions

  • J99 — Respiratory disorders in diseases classified elsewhere [Code First](via M45.-): “ankylosing spondylitis (M45.-)” · check together

Clinical classification (CCSR)

  • MUS011 — Spondylopathies/spondyloarthropathy (including infective) [CCSR]
  • MUS003 — Rheumatoid arthritis and related disease [CCSR]

Risk adjustment (CMS-HCC)

  • HCC 93 — Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders [CMS-HCC]: “Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders — supersedes HCC 94 (Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders)”

Potential MS-DRG

  • DRG 545 — CONNECTIVE TISSUE DISORDERS WITH MCC [MS-DRG]: “CONNECTIVE TISSUE DISORDERS WITH MCC (MDC 08)”
  • DRG 546 — CONNECTIVE TISSUE DISORDERS WITH CC [MS-DRG]: “CONNECTIVE TISSUE DISORDERS WITH CC (MDC 08)”
  • DRG 547 — CONNECTIVE TISSUE DISORDERS WITHOUT CC/MCC [MS-DRG]: “CONNECTIVE TISSUE DISORDERS WITHOUT CC/MCC (MDC 08)”

MDC crossing · procedures (18508)

  • MDC 08 — Diseases and Disorders of the Musculoskeletal System and Connective Tissue [MDC crossing]: “Diseases and Disorders of the Musculoskeletal System and Connective Tissue — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs.”
  • 005T0ZZ — Destruction of Spinal Meninges, Open Approach [Same-MDC procedure]: “Destruction of Spinal Meninges, Open Approach — grouped in MDC 08, the procedure side of this code's crossing.” · check together
  • 005T3ZZ — Destruction of Spinal Meninges, Percutaneous Approach [Same-MDC procedure]: “Destruction of Spinal Meninges, Percutaneous Approach — grouped in MDC 08, the procedure side of this code's crossing.” · check together
  • 005T4ZZ — Destruction of Spinal Meninges, Percutaneous Endoscopic Approach [Same-MDC procedure]: “Destruction of Spinal Meninges, Percutaneous Endoscopic Approach — grouped in MDC 08, the procedure side of this code's crossing.” · check together
  • 005W0Z3 — Destruction of Cervical Spinal Cord using Laser Interstitial Thermal Therapy, Open Approach [Same-MDC procedure]: “Destruction of Cervical Spinal Cord using Laser Interstitial Thermal Therapy, Open Approach — grouped in MDC 08, the procedure side of this code's crossing.” · check together
  • 005W0ZZ — Destruction of Cervical Spinal Cord, Open Approach [Same-MDC procedure]: “Destruction of Cervical Spinal Cord, Open Approach — grouped in MDC 08, the procedure side of this code's crossing.” · check together
  • and 18503 more

Index entries

  • Spondyloarthritis, axial, non-radiographic[Index term]

Nearest codes (21)

  • M45 — Ankylosing spondylitis [Sibling]
  • M45.0 — Ankylosing spondylitis of multiple sites in spine [Sibling]
  • M45.1 — Ankylosing spondylitis of occipito-atlanto-axial region [Sibling]
  • M45.2 — Ankylosing spondylitis of cervical region [Sibling]
  • M45.3 — Ankylosing spondylitis of cervicothoracic region [Sibling]
  • M45.4 — Ankylosing spondylitis of thoracic region [Sibling]
  • M45.5 — Ankylosing spondylitis of thoracolumbar region [Sibling]
  • M45.6 — Ankylosing spondylitis lumbar region [Sibling]
  • and 13 more

Change history

  • FY2022 — Added to the code set [Change history]

Nearest Codes in This Family

Official ICD-10-CM classifications closest to M45.A0 in its code family, with their registry titles.

  • M45.6 — Ankylosing spondylitis lumbar region
  • M45.7 — Ankylosing spondylitis of lumbosacral region
  • M45.8 — Ankylosing spondylitis sacral and sacrococcygeal region
  • M45.9 — Ankylosing spondylitis of unspecified sites in spine
  • M45.A — Non-radiographic axial spondyloarthritis
  • M45.A1 — Non-radiographic axial spondyloarthritis of occipito-atlanto-axial region
  • M45.A2 — Non-radiographic axial spondyloarthritis of cervical region
  • M45.A3 — Non-radiographic axial spondyloarthritis of cervicothoracic region
  • M45.A4 — Non-radiographic axial spondyloarthritis of thoracic region
  • M45.A5 — Non-radiographic axial spondyloarthritis of thoracolumbar region

View all codes in the M45 family