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ICD-10/M45.A8

M45.A8 ICD-10-CM Code: Non-radiographic axial spondyloarthritis of sacral and sacrococcygeal region

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 sacral and sacrococcygeal region is a billable ICD-10-CM diagnosis code (M45.A8).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for M45.A8 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.

Change history

  • FY2022 — 2021-10-01
    Added to the code set
    Non-radiographic axial spondyloarthritis of sacral and sacrococcygeal region
    FY2022 changes

Verify Before Coding

  • Billable — reportable as written.

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

Contextual Map

Every relationship of M45.A8 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

  • M45.A — Non-radiographic axial spondyloarthritis [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.-)”
  • M05 — Rheumatoid arthritis with rheumatoid factor [Excludes1](via M45.-): “rheumatoid arthritis of spine (M45.-)”

Referenced by Code First instructions

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

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]

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)”

Index entries

  • Spondyloarthritis, axial, n… — Spondyloarthritis, axial, non-radiographic, sacral and sacrococcygeal [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]

Referenced by Other Codes

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.

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.

Official ICD-10-CM tabular notes on other codes that name M45.A8 or its code family.

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

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

Nearest Codes in This Family

Official ICD-10-CM classifications closest to M45.A8 in its code family, with their registry titles.

  • M45.A — Non-radiographic axial spondyloarthritis
  • M45.A0 — Non-radiographic axial spondyloarthritis of unspecified sites in spine
  • 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
  • M45.A6 — Non-radiographic axial spondyloarthritis of lumbar region
  • M45.A7 — Non-radiographic axial spondyloarthritis of lumbosacral region
  • M45.AB — Non-radiographic axial spondyloarthritis of multiple sites in spine

View all codes in the M45 family

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, sacral and sacrococcygeal