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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.

Coding at a Glance

Tabular directives
2 inclusion terms · 1 Excludes2 · 8 use-additional codes
Risk adjustment
CMS-HCC V28: 1 category · RxHCC V08 category 112

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, 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.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for G31.83 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on G31.83 itself; “inherited from” names the category or block whose note applies here.

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.

Source: inherited from G31

Use Additional Code

Supplementary codes the tabular list directs you to add.

Coder workflow for G31.83

MedCoder structured workflow — derived from this code’s own official record

Before you code G31.83

  1. G31.83’s title joins a condition with an associated condition or complication. Confirm each component is documented. Where the classification presumes the link through the “with” convention, only a provider statement that the conditions are unrelated defeats it. A combination code is assigned only when it fully identifies the documented conditions; a required second code for the stage, type or manifestation is still reported when the notes ask for it (Guidelines I.B.9, I.A.15).

    Guide: Combination codes →

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
The associated condition or complication
Whether the associated condition the title names is documented; the “with” convention presumes some links, and a provider statement that the conditions are unrelated defeats it (Guidelines I.A.15).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.

Official instructions as workflow

  • Excludes2 — not part of G31.83(1 note)

    Coding workflow: The conditions named in this note are not included in G31.83. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareG93.7

    See the official tabular notes · Guidelines I.A.12.b

  • Use Additional Code — after identifying G31.83(8 notes)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with G31.83 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewF06.7, F02.84, F02.A4, F02.B4, F02.C4, F02.81

    See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: Only one of the components this code’s title joins is documented.

Coding question: Is G31.83 supported?

Path: Review the code for the documented component on its own.

Reason: A combination code is assigned only when it fully identifies the documented conditions; otherwise the documented component takes its own code (Guidelines I.B.9).

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with G31.83?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

ReviewF06.7, F02.84, F02.A4, F02.B4, F02.C4, F02.81

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

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

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Indexed Clinical Terms (8)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name G31.83 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes1 note: G21 — Secondary parkinsonism.

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 2 Code First instructions: F02 — Dementia in other diseases classified elsewhere, F06.7 — Mild neurocognitive disorder due to known physiological condition.

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 2 MS-DRGs: DRG 056 (MDC 01), DRG 057 (MDC 01).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):NVS011 — Neurocognitive disorders (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Dementia, Mild or Unspecified) for risk-adjusted payment.

F03.A3 — Unspecified dementia, mild, with mood disturbance, F03.A4 — Unspecified dementia, mild, with anxiety, G30.0 — Alzheimer's disease with early onset, G30.1 — Alzheimer's disease with late onset, G30.8 — Other Alzheimer's disease, G30.9 — Alzheimer's disease, unspecified, G31.01 — Pick's disease, G31.09 — Other frontotemporal neurocognitive disorder, G31.81 — Alpers disease, G31.82 — Leigh's disease, G31.86 — Alexander disease, G91.0 — Communicating hydrocephalus, G91.1 — Obstructive hydrocephalus, G91.2 — (Idiopathic) normal pressure hydrocephalus, G91.3 — Post-traumatic hydrocephalus, unspecified, G91.4 — Hydrocephalus in diseases classified elsewhere, G91.8 — Other hydrocephalus, G91.9 — Hydrocephalus, unspecified, G93.7 — Reye's syndrome, I67.3 — Progressive vascular leukoencephalopathy, +44 more

Related risk categories

These categories interact through CMS's HCC hierarchy — one can suppress the other's risk-adjustment weight when both are present on a claim.

Dementia, Severe, Dementia, Moderate

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Neurocognitive disorders).

F06.70 — Mild neurocognitive disorder due to known physiological condition without behavioral disturbance, F06.71 — Mild neurocognitive disorder due to known physiological condition with behavioral disturbance, F07.81 — Postconcussional syndrome, F07.89 — Other personality and behavioral disorders due to known physiological condition, F19.17 — Other psychoactive substance abuse with psychoactive substance-induced persisting dementia, F19.27 — Other psychoactive substance dependence with psychoactive substance-induced persisting dementia, F19.97 — Other psychoactive substance use, unspecified with psychoactive substance-induced persisting dementia, F48.2 — Pseudobulbar affect, G11.6 — Leukodystrophy with vanishing white matter disease, G30.0 — Alzheimer's disease with early onset, G30.1 — Alzheimer's disease with late onset, G30.8 — Other Alzheimer's disease, G30.9 — Alzheimer's disease, unspecified, G31.01 — Pick's disease, G31.09 — Other frontotemporal neurocognitive disorder, G31.1 — Senile degeneration of brain, not elsewhere classified, G31.81 — Alpers disease, G31.84 — Mild cognitive impairment of uncertain or unknown etiology, G31.86 — Alexander disease, G31.9 — Degenerative disease of nervous system, unspecified, +77 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Dementia”; these codes share that main term but sit in a different category of the Tabular List.

F03.C11 — Unspecified dementia, severe, with agitation (severe, with, agitation), F03.C18 — Unspecified dementia, severe, with other behavioral disturbance (severe, with, behavioral disturbances), F03.C2 — Unspecified dementia, severe, with psychotic disturbance (severe, with, psychotic disturbance), F03.C3 — Unspecified dementia, severe, with mood disturbance (severe, with, mood disturbance), F03.C4 — Unspecified dementia, severe, with anxiety (severe, with, anxiety), F05 — Delirium due to known physiological condition (with, acute confusional state), F10.27 — Alcohol dependence with alcohol-induced persisting dementia (alcoholic, with dependence), F10.97 — Alcohol use, unspecified with alcohol-induced persisting dementia (alcoholic), F13.27 — Sedative, hypnotic or anxiolytic dependence with sedative, hypnotic or anxiolytic-induced persisting dementia (in, sedatives, hypnotics or anxiolytics, with dependence), F13.97 — Sedative, hypnotic or anxiolytic use, unspecified with sedative, hypnotic or anxiolytic-induced persisting dementia (in, sedatives, hypnotics or anxiolytics), F18.27 — Inhalant dependence with inhalant-induced dementia (in, inhalants, with dependence), F18.97 — Inhalant use, unspecified with inhalant-induced persisting dementia (in, inhalants), F19.27 — Other psychoactive substance dependence with psychoactive substance-induced persisting dementia (in, psychoactive drug, with dependence), F19.97 — Other psychoactive substance use, unspecified with psychoactive substance-induced persisting dementia (in, psychoactive drug), F84.3 — Other childhood disintegrative disorder (infantile, infantilis), G10 — Huntington's disease (in, Huntington's disease or chorea), G20.A1 — Parkinson's disease without dyskinesia, without mention of fluctuations (in, Parkinson's disease), G20.C — Parkinsonism, unspecified (with, Parkinsonism), G35.D — Multiple sclerosis, unspecified (in, multiple, sclerosis), M30.0 — Polyarteritis nodosa (in, polyarteritis nodosa), +80 more

Contextual Map

Every relationship of G31.83 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.

Run G31.83 with these 3 related codes in Claim Check

Hierarchy

Use Additional Code

Referenced by Excludes1 notes

  • G21 — Secondary parkinsonism[Excludes1]: “neurocognitive disorder with Lewy bodies (G31.83)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Code First instructions

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

  • HCC 127 — Dementia, Mild or Unspecified [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

MDC crossing

  • 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. 8,892 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

  • Dementia (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety), Lewy body[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Dementia (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety), Lewy body, with behavioral disturbance[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Dementia (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety), with, Lewy bodies[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Dementia (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety), with, Lewy bodies, with behavioral disturbance[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Disease, diseased, Lewy body (dementia)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Disease, diseased, Lewy body (dementia), with behavioral disturbance[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Disorder (of), neurocognitive, with Lewy bodies[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Lewy body (ies) (disease)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (16)

Change history (3)

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page
Risk adjustment Official source data
2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "G31.83 — Neurocognitive disorder with Lewy bodies." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/g31.83-neurocognitive-disorder-with-lewy-bodies

Change history

  • FY2023 — October 1, 2022
    Description revised
    Dementia with Lewy bodies → Neurocognitive disorder with Lewy bodies
    FY2023 changes
  • FY2023 — October 1, 2022
    Short description revised
    Dementia with Lewy bodies → Neurocognitive disorder with Lewy bodies
    FY2023 changes
  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Dementia with Lewy bodies

Nearest Codes in This Family

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

View all codes in the G31 family