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ICD-10/G31.83

G31.83 ICD-10-CM Code: Neurocognitive disorder with Lewy bodies

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 (FY2026), Appendix B.

  • MS-DRG 056 — DEGENERATIVE NERVOUS SYSTEM DISORDERS WITH MCC (MDC 01)
  • MS-DRG 057 — DEGENERATIVE NERVOUS SYSTEM DISORDERS WITHOUT 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 127 — Dementia, Mild or Unspecified

Other models: RxHCC V08 HCC 112

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Code Set: Valid FY2026 and FY2027. FY2026 took effect October 1, 2025.

Official Registry Overview & Definition

Neurocognitive disorder with Lewy bodies is a billable ICD-10-CM diagnosis code (G31.83).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for G31.83 in the official ICD-10-CM tabular list.

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Lewy body dementia
  • Lewy body disease

Excludes2 — Not Included Here

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

  • Reye's syndrome (G93.7)

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code, if applicable, to identify mild neurocognitive disorders due to known physiological condition (F06.7-)
  • Use additional code, if applicable, for codes G31.0-G31.83, G31.85-G31.9, to identify:
  • dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4)
  • dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-)
  • dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3)
  • dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2)
  • dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0)
  • mild neurocognitive disorder due to known physiological condition (F06.7-)

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G31.83 in its code family, with their registry titles.

  • G31.2 — Degeneration of nervous system due to alcohol
  • G31.8 — Other specified degenerative diseases of nervous system
  • G31.80 — Leukodystrophy, unspecified
  • G31.81 — Alpers disease
  • G31.82 — Leigh's disease
  • G31.84 — Mild cognitive impairment of uncertain or unknown etiology
  • G31.85 — Corticobasal degeneration
  • G31.86 — Alexander disease
  • G31.87 — Primary progressive apraxia of speech
  • G31.89 — Other specified degenerative diseases of nervous system

View all codes in the G31 family

Indexed Clinical Terms (8)

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

  • Dementia (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety), Lewy body
  • Dementia (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety), Lewy body, with behavioral disturbance
  • Dementia (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety), with, Lewy bodies
  • Dementia (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety), with, Lewy bodies, with behavioral disturbance
  • Disease, diseased, Lewy body (dementia)
  • Disease, diseased, Lewy body (dementia), with behavioral disturbance
  • Disorder (of), neurocognitive, with Lewy bodies
  • Lewy body (ies) (disease)