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G71.21 ICD-10-CM Code: Nemaline myopathy

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 091 — OTHER DISORDERS OF NERVOUS SYSTEM WITH MCC (MDC 01)
  • MS-DRG 092 — OTHER DISORDERS OF NERVOUS SYSTEM WITH CC (MDC 01)
  • MS-DRG 093 — OTHER DISORDERS OF NERVOUS SYSTEM WITHOUT CC/MCC (MDC 01)

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 197 — Muscular Dystrophy

Other models: CMS-HCC V22 HCC 76

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

Nemaline myopathy is a billable ICD-10-CM diagnosis code (G71.21).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for G71.21 in the official ICD-10-CM tabular list.

Excludes2 — Not Included Here

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

Frequently Compared Codes

The official Excludes notes on G71.21 name these codes. Each comparison page covers when the two can — or must not — be reported together.

Change history

  • FY2021 — 2020-10-01
    Added to the code set
    Nemaline myopathy
    FY2021 changes

Verify Before Coding

  • CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

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 G71.21 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

  • G00-G99 — Chapter 6: Diseases of the Nervous System (G00-G99) (G00-G99) [Hierarchy]

Referenced by Excludes2 notes

  • M60 — Myositis [Excludes2](via G71.-): “muscular dystrophies and myopathies (G71-G72)” · check together
  • M60-M63 — Disorders of muscles (M60-M63) [Excludes2](via G71.-): “muscular dystrophies and myopathies (G71-G72)” · check together
  • M61 — Calcification and ossification of muscle [Excludes2](via G71.-): “muscular dystrophies and myopathies (G71-G72)” · check together
  • M62 — Other disorders of muscle [Excludes2](via G71.-): “muscular dystrophies and myopathies (G71-G72)” · check together
  • M63 — Disorders of muscle in diseases classified elsewhere [Excludes2](via G71.-): “muscular dystrophies and myopathies (G71-G72)” · check together

Referenced by Code First instructions

  • M62.84 — Sarcopenia [Code First](via G71.-): “primary disorders of muscles (G71.-)” · check together

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

  • HCC 197 — Muscular Dystrophy [CMS-HCC]

Potential MS-DRG

  • CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”
  • DRG 091 — OTHER DISORDERS OF NERVOUS SYSTEM WITH MCC [MS-DRG]: “OTHER DISORDERS OF NERVOUS SYSTEM WITH MCC (MDC 01)”
  • DRG 092 — OTHER DISORDERS OF NERVOUS SYSTEM WITH CC [MS-DRG]: “OTHER DISORDERS OF NERVOUS SYSTEM WITH CC (MDC 01)”
  • DRG 093 — OTHER DISORDERS OF NERVOUS SYSTEM WITHOUT CC/MCC [MS-DRG]: “OTHER DISORDERS OF NERVOUS SYSTEM WITHOUT CC/MCC (MDC 01)”

MDC crossing · procedures (8892)

  • MDC 01 — Diseases and Disorders of the Nervous System [MDC crossing]: “Diseases and Disorders of the Nervous System — 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.”
  • 0016070 — Bypass Cerebral Ventricle to Nasopharynx with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Nasopharynx with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016071 — Bypass Cerebral Ventricle to Mastoid Sinus with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Mastoid Sinus with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016072 — Bypass Cerebral Ventricle to Atrium with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Atrium with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016073 — Bypass Cerebral Ventricle to Blood Vessel with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Blood Vessel with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016074 — Bypass Cerebral Ventricle to Pleural Cavity with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Pleural Cavity with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • and 8887 more

Index entries

  • Disease, diseased, nemaline body[Index term]
  • Disease, diseased, rod body[Index term]
  • Myopathy, nemaline[Index term]
  • Myopathy, rod (body)[Index term]

Nearest codes (34)

  • G71 — Primary disorders of muscles [Sibling]
  • G71.0 — Muscular dystrophy [Sibling]
  • G71.00 — Muscular dystrophy, unspecified [Sibling]
  • G71.01 — Duchenne or Becker muscular dystrophy [Sibling]
  • G71.02 — Facioscapulohumeral muscular dystrophy [Sibling]
  • G71.03 — Limb girdle muscular dystrophies [Sibling]
  • G71.031 — Autosomal dominant limb girdle muscular dystrophy [Sibling]
  • G71.032 — Autosomal recessive limb girdle muscular dystrophy due to calpain-3 dysfunction [Sibling]
  • and 26 more

Change history

  • FY2021 — Added to the code set [Change history]

Referenced by Other Codes

Clinical classification (AHRQ CCSR):NVS018 — Myopathies (default).

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)

CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 22 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 091 (MDC 01), DRG 092 (MDC 01), DRG 093 (MDC 01).

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 G71.21 or its code family.

5 Excludes2 notes: M60 (via G71.-), M60-M63 (via G71.-), M61 (via G71.-), M62 (via G71.-), M63 (via G71.-).

1 Code First instructions: M62.84 (via G71.-).

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G71.21 in its code family, with their registry titles.

  • G71.13 — Myotonic chondrodystrophy
  • G71.14 — Drug induced myotonia
  • G71.19 — Other specified myotonic disorders
  • G71.2 — Congenital myopathies
  • G71.20 — Congenital myopathy, unspecified
  • G71.22 — Centronuclear myopathy
  • G71.220 — X-linked myotubular myopathy
  • G71.228 — Other centronuclear myopathy
  • G71.29 — Other congenital myopathy
  • G71.3 — Mitochondrial myopathy, not elsewhere classified

View all codes in the G71 family

Indexed Clinical Terms (4)

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

  • Disease, diseased, nemaline body
  • Disease, diseased, rod body
  • Myopathy, nemaline
  • Myopathy, rod (body)