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ICD-10-CM 2027 diagnosis code

M45.6Ankylosing spondylitis lumbar region

✓ Billable / specific

M45.6 is a valid, billable ICD-10-CM code for ankylosing spondylitis lumbar region. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About M45.6

M45.6 is the ICD-10-CM diagnosis code for ankylosing spondylitis lumbar region. 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 (ankylosing spondylitis), M45.6 is specifically for ankylosing spondylitis lumbar region. Related codes cover of multiple sites in spine (M45.0), of occipito-atlanto-axial region (M45.1), of cervical region (M45.2), of cervicothoracic region (M45.3), of thoracic region (M45.4), of thoracolumbar region (M45.5), of lumbosacral region (M45.7), sacral and sacrococcygeal region (M45.8) and 2 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 has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 720.0 (ankylosing spondylitis).

Notes that apply from higher levels

Instructions written at a parent level also apply to M45.6.

› 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 M45.6.

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.

ICD-9-CM equivalent

Converter →
  • 720.0Ankylosing spondylitisapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

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
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about M45.6

Is M45.6 billable?

Yes. M45.6 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can M45.6 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict M45.6 as a principal diagnosis.

Is M45.6 a CC or MCC?

No. M45.6 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does M45.6 group to?

M45.6 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.

What is the ICD-9 code for M45.6?

The CMS General Equivalence Mappings map M45.6 to ICD-9-CM 720.0.