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G93.40 ICD-10-CM Code: Encephalopathy, unspecified

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
4 Excludes2

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 v44, Appendix B.

  • MS-DRG 070 — OTHER CEREBROVASCULAR DISORDERS WITH MCC (MDC 01)
  • MS-DRG 071 — OTHER CEREBROVASCULAR DISORDERS WITH CC (MDC 01)
  • MS-DRG 072 — OTHER CEREBROVASCULAR DISORDERS WITHOUT CC/MCC (MDC 01)
  • MS-DRG 974 — HIV WITH MAJOR RELATED CONDITION WITH MCC (MDC 25)
  • MS-DRG 975 — HIV WITH MAJOR RELATED CONDITION WITH CC (MDC 25)
  • MS-DRG 976 — HIV WITH MAJOR RELATED CONDITION WITHOUT CC/MCC (MDC 25)

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.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for G93.40 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on G93.40 itself; “inherited from” names the category or block whose note applies here.

Excludes2 — Not Included Here

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

Source: inherited from G93.4

Coder workflow for G93.40

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

Before you code G93.40

  1. Unspecified does not mean incorrect. When the record gives no greater specificity, G93.40 may be the appropriate code. Check the record for detail that supports a more specific sibling — in this subcategory the siblings differ by the presence or absence of the associated condition. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).

    ReviewG93.41, G93.42, G93.43, G93.44, G93.45, G93.49

    See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

Choose the right path

  1. Does the record document the detail a more specific sibling code needs?
    Yes → Review the specific siblings in this subcategory.
    No → Continue — G93.40 is appropriate when the documentation goes no further.

    ReviewG93.41, G93.42, G93.43, G93.44, G93.45, G93.49

Consider G93.40. Then confirm the code is valid for the date of service in the Verify section.

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).
Any detail beyond this code’s title
What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

  • Excludes2 — not part of G93.40(4 notes)

    Coding workflow: The conditions named in this note are not included in G93.40. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareG31.2, G94, I67.4, G92.8

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

Coding decision scenarios

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

Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the specific siblings in this subcategory and what each requires the record to state.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

ReviewG93.41, G93.42, G93.43, G93.44, G93.45, G93.49

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.

Don’t confuse G93.40 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of G93.40 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

  • G31.2— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of alcoholic encephalopathy adds G31.2; it is not part of this code and both may be reported when both are documented.

    Full comparison: G93.40 vs G31.2 →

  • G94— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of encephalopathy in diseases classified elsewhere adds G94; it is not part of this code and both may be reported when both are documented.

    Full comparison: G93.40 vs G94 →

  • I67.4— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of hypertensive encephalopathy adds I67.4; it is not part of this code and both may be reported when both are documented.

    Full comparison: G93.40 vs I67.4 →

  • G92.8— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of toxic (metabolic) encephalopathy adds G92.8; it is not part of this code and both may be reported when both are documented.

    Full comparison: G93.40 vs G92.8 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Code Overview

Encephalopathy, unspecified is a billable ICD-10-CM diagnosis code (G93.40).

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 (1)

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

  • CC as a secondary diagnosis (FY2027). 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 in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name G93.40 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: G04 — Encephalitis, myelitis and encephalomyelitis.

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

Referenced by 1 Code Also instruction: F78.A1 — SYNGAP1-related intellectual disability (via G93.4.-).

These codes suggest coding this condition alongside when both are present.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: 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 10 clinically related codes on its CMS exclusion list. Does not count toward severity when the stay groups to DRGs 974-976 (HIV with Major Related Condition).

Named in the grouper logic of 6 MS-DRGs: DRG 070 (MDC 01), DRG 071 (MDC 01), DRG 072 (MDC 01), DRG 974 (MDC 25), DRG 975 (MDC 25), DRG 976 (MDC 25).

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

Clinical classification (AHRQ CCSR):NVS020 — Other nervous system disorders (neither hereditary nor degenerative) (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 clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

G21.0 — Malignant neuroleptic syndrome, G83.5 — Locked-in state, G93.41 — Metabolic encephalopathy, G93.42 — Megalencephalic leukoencephalopathy with subcortical cysts, G93.43 — Leukoencephalopathy with calcifications and cysts, G93.44 — Adult-onset leukodystrophy with axonal spheroids, G93.45 — Developmental and epileptic encephalopathy, G93.49 — Other encephalopathy, I67.83 — Posterior reversible encephalopathy syndrome

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Other nervous system disorders (neither hereditary nor degenerative)).

G92.04 — Immune effector cell-associated neurotoxicity syndrome, grade 4, G92.05 — Immune effector cell-associated neurotoxicity syndrome, grade 5, G92.8 — Other toxic encephalopathy, G92.9 — Unspecified toxic encephalopathy, G93.0 — Cerebral cysts, G93.2 — Benign intracranial hypertension, G93.3 — Postviral and related fatigue syndromes, G93.31 — Postviral fatigue syndrome, G93.32 — Myalgic encephalomyelitis/chronic fatigue syndrome, G93.39 — Other post infection and related fatigue syndromes, G93.41 — Metabolic encephalopathy, G93.49 — Other encephalopathy, G93.5 — Compression of brain, G93.6 — Cerebral edema, G93.7 — Reye's syndrome, G93.81 — Temporal sclerosis, G93.82 — Brain death, G93.89 — Other specified disorders of brain, G93.9 — Disorder of brain, unspecified, G94 — Other disorders of brain in diseases classified elsewhere, +97 more

Same Index main term, other category

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

G04.31 — Postinfectious acute necrotizing hemorrhagic encephalopathy (acute necrotizing hemorrhagic, postinfectious), G04.32 — Postimmunization acute necrotizing hemorrhagic encephalopathy (acute necrotizing hemorrhagic, postimmunization), G04.39 — Other acute necrotizing hemorrhagic encephalopathy (acute necrotizing hemorrhagic, specified NEC), G31.2 — Degeneration of nervous system due to alcohol (alcoholic), G31.82 — Leigh's disease (necrotizing, subacute), G32.89 — Other specified degenerative disorders of nervous system in diseases classified elsewhere (degenerative, in specified disease NEC), G37.0 — Diffuse sclerosis of central nervous system (centrolobar progressive), G37.1 — Central demyelination of corpus callosum (demyelinating callosal), G92.8 — Other toxic encephalopathy (due to, drugs), G92.9 — Unspecified toxic encephalopathy (toxic), I67.2 — Cerebral atherosclerosis (arteriosclerotic), I67.4 — Hypertensive encephalopathy (hypertensive), K76.82 — Hepatic encephalopathy (hepatic), P11.1 — Other specified brain damage due to birth injury (in, birth injury), P57.0 — Kernicterus due to isoimmunization (hyperbilirubinemic, newborn, due to isoimmunization), P57.9 — Kernicterus, unspecified (hyperbilirubinemic, newborn), P91.60 — Hypoxic ischemic encephalopathy [HIE], unspecified (hypoxic ischemic), P91.61 — Mild hypoxic ischemic encephalopathy [HIE] (hypoxic ischemic, mild), P91.62 — Moderate hypoxic ischemic encephalopathy [HIE] (hypoxic ischemic, moderate), P91.63 — Severe hypoxic ischemic encephalopathy [HIE] (hypoxic ischemic, severe), +17 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

HIV Screening Test

Contextual Map

Every relationship of G93.40 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 G93.40 with these 2 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Code Also instructions

Clinical classification (CCSR)

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. 8,919 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027
  • MDC 25 — Human Immunodeficiency Virus Infections[MDC crossing]: “Human Immunodeficiency Virus Infections — 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.”— CMS MS-DRG Definitions Manual · FY2027

Index entries

  • Encephalopathy (acute)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027

Nearest codes (23)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

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 FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 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 — v44 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. "G93.40 — Encephalopathy, unspecified." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/g93.40-encephalopathy-unspecified

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Encephalopathy, unspecified

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G93.40 in its code family, with their registry titles.

View all codes in the G93 family