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ICD-10-CM 2027 diagnosis code

M51.A2Intervertebral annulus fibrosus defect, large, lumbar region

✓ Billable / specific

M51.A2 is a valid, billable ICD-10-CM code for intervertebral annulus fibrosus defect, large, lumbar region. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code last changed in FY2023 (effective October 1, 2022). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About M51.A2

M51.A2 is the ICD-10-CM diagnosis code for intervertebral annulus fibrosus defect, large, lumbar region. It belongs to category M51 (thoracic, thoracolumbar, and lumbosacral intervertebral disc disorders), block M50-M54 (other dorsopathies) 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 M51.A (other lumbar and lumbosacral annulus fibrosus disc defects), M51.A2 is specifically for intervertebral annulus fibrosus defect, large, lumbar region. Related codes cover lumbar region, unspecified size (M51.A0), small, lumbar region (M51.A1), lumbosacral region, unspecified size (M51.A3), small, lumbosacral region (M51.A4) and large, lumbosacral region (M51.A5).

Code first: , if applicable, lumbar disc herniation (M51.06, M51.16, M51.26).

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 551 (Medical Back Problems with MCC, relative weight 1.6358) and DRG 552 (Medical Back Problems without MCC, relative weight 0.9584), 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 FY2023, effective October 1, 2022.

Coding notes

Code firstSequence the underlying condition first

Notes that apply from higher levels

Instructions written at a parent level also apply to M51.A2.

› From M51 Thoracic, thoracolumbar, and lumbosacral intervertebral disc disorders
Excludes2
  • cervical and cervicothoracic disc disorders (M50.-)
  • sacral and sacrococcygeal disorders (M53.3)

Broader instructions also apply from M50-M54 Other dorsopathies and 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 M51.A2.

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.

MDC 08 · Diseases and Disorders of the Musculoskeletal System and Connective Tissue

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
  • FY2023 (effective 10/1/2022): Added
  • No changes since FY2023.

Common questions about M51.A2

Is M51.A2 billable?

Yes. M51.A2 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can M51.A2 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict M51.A2 as a principal diagnosis.

Is M51.A2 a CC or MCC?

No. M51.A2 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does M51.A2 group to?

M51.A2 is used in the MS-DRG v44.0 logic for MS-DRG 551 (Medical Back Problems with MCC) and MS-DRG 552 (Medical Back Problems without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.