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ICD-10-CM 2027 diagnosis code

M45.A0Non-radiographic axial spondyloarthritis of unspecified sites in spine

✓ Billable / specific

M45.A0 is a valid, billable ICD-10-CM code for non-radiographic axial spondyloarthritis of unspecified sites in spine. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.Short description: Non-radiographic axial spondyloarthritis unsp site in spin

Code last changed in FY2022 (effective October 1, 2021). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About M45.A0

M45.A0 is the ICD-10-CM diagnosis code for Non-radiographic axial spondyloarthritis of unspecified sites in spine. It belongs to category M45 (ankylosing spondylitis), block M45-M49 (spondylopathies) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within M45.A, choose M45.A0 (of unspecified sites in spine) only when documentation doesn't support a more specific option: of occipito-atlanto-axial region (M45.A1), of cervical region (M45.A2), of cervicothoracic region (M45.A3), of thoracic region (M45.A4), of thoracolumbar region (M45.A5), of lumbar region (M45.A6), of lumbosacral region (M45.A7), of sacral and sacrococcygeal region (M45.A8) and 1 more.

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 545 (Connective Tissue Disorders with MCC, relative weight 2.3892), DRG 546 (Connective Tissue Disorders with CC, relative weight 1.1745) and DRG 547 (Connective Tissue Disorders without CC/MCC, relative weight 0.7526), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It was added in FY2022, effective October 1, 2021.

Notes that apply from higher levels

Instructions written at a parent level also apply to M45.A0.

› From M45 Ankylosing spondylitis
Excludes1
  • arthropathy in Reiter's disease (M02.3-)
  • juvenile (ankylosing) spondylitis (M08.1)
Excludes2
  • Behçet's disease (M35.2)

Broader instructions also apply from Chapter 13: Diseases of the musculoskeletal system and connective tissue.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to M45.A0.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2022 (effective 10/1/2021): Added
  • No changes since FY2022.

Common questions about M45.A0

Is M45.A0 billable?

Yes. M45.A0 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can M45.A0 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict M45.A0 as a principal diagnosis.

Is M45.A0 a CC or MCC?

No. M45.A0 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does M45.A0 group to?

M45.A0 is used in the MS-DRG v44.0 logic for MS-DRG 545 (Connective Tissue Disorders with MCC), MS-DRG 546 (Connective Tissue Disorders with CC) and MS-DRG 547 (Connective Tissue Disorders without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.