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F05 ICD-10-CM Code: Delirium due to known physiological condition

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

Coding at a Glance

Tabular directives
8 inclusion terms · 1 Excludes1 · 1 Excludes2 · 2 code-first instructions

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 880 — ACUTE ADJUSTMENT REACTION AND PSYCHOSOCIAL DYSFUNCTION (MDC 19)

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 F05 in the official ICD-10-CM tabular list, quoted as published.

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

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Acute or subacute brain syndrome
  • Acute or subacute confusional state (nonalcoholic)
  • Acute or subacute infective psychosis
  • Acute or subacute organic reaction
  • Acute or subacute psycho-organic syndrome
  • Delirium of mixed etiology
  • Delirium superimposed on dementia
  • Sundowning

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

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

Code First

Underlying conditions that must be sequenced before this code.

  • the underlying physiological condition, such as:
  • dementia (F03.9-)

Coder workflow for F05

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

Before you code F05

  1. F05’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 →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with F05. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support a condition named in F05’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewR41.0

  2. Is the underlying (etiologic) condition the Code First note names documented?
    Yes → Sequence the underlying condition first, then F05.
    No → Continue; do not add an underlying condition the record does not document.

    ReviewF03.9

Consider F05. 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).
The underlying (etiologic) condition
Named in the Code First note; sequenced before this code when documented (Guidelines I.A.13).

Official instructions as workflow

  • Excludes1 — check before selecting F05(1 note)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with F05: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareR41.0

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

  • Excludes2 — not part of F05(1 note)

    Coding workflow: The conditions named in this note are not included in F05. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareF10.231, F10.921

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

  • Code First — sequencing check(2 notes)

    Coding workflow: Check whether the underlying or etiologic condition the note names is documented. When it is, sequence it before F05. Do not add an underlying condition the record does not document.

    ReviewF03.9

    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: Both the condition F05 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewR41.0

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

Coding question: Is F05 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: The underlying condition the Code First note names is documented alongside this condition.

Coding question: How are the two sequenced?

Path: Review the Code First note.

Reason: The underlying condition is sequenced first and the manifestation follows (Guidelines I.A.13).

ReviewF03.9

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

Delirium due to known physiological condition is a billable ICD-10-CM diagnosis code (F05).

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 (26)

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.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. Sequencing: 2 Code First instructions — the underlying condition is sequenced before this code when present. See the Code First notes
  2. 1 Excludes1 entry — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
  3. 1 Excludes2 entry — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

  • Principal-diagnosis restriction. The Medicare Code Editor lists this code as unacceptable as a principal diagnosis: it describes a circumstance influencing health status rather than a current illness or injury being treated. It is valid as a secondary diagnosis.
  • 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 in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name F05 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: R41.0 — Disorientation, unspecified.

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

Referenced by 4 Excludes2 notes: F03 — Unspecified dementia, F06 — Other mental disorders due to known physiological condition, F63.1 — Pyromania, F63.2 — Kleptomania.

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 2 Use Additional Code instructions across 2 chapters: G30 — Alzheimer's disease, T81.89 — Other complications of procedures, not elsewhere classified.

These codes instruct coders to additionally report this code when it applies.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 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 1 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 1 MS-DRG: DRG 880 (MDC 19).

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 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.

R45.851 — Suicidal ideations

Principal diagnosis restriction (Medicare Code Editor)

Not acceptable as a principal diagnosis on an inpatient claim.

Same clinical category (CCSR)

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

F03.B2 — Unspecified dementia, moderate, with psychotic disturbance, F03.B3 — Unspecified dementia, moderate, with mood disturbance, F03.B4 — Unspecified dementia, moderate, with anxiety, F03.C0 — Unspecified dementia, severe, without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety, F03.C11 — Unspecified dementia, severe, with agitation, F03.C18 — Unspecified dementia, severe, with other behavioral disturbance, F03.C2 — Unspecified dementia, severe, with psychotic disturbance, F03.C3 — Unspecified dementia, severe, with mood disturbance, F03.C4 — Unspecified dementia, severe, with anxiety, F04 — Amnestic disorder due to known physiological condition, 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, +77 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main terms “State”, “Psychosis, psychotic”, “Delirium, delirious”, …; these codes share that main term but sit in a different category of the Tabular List.

F03.B2 — Unspecified dementia, moderate, with psychotic disturbance (moderate, with, psychotic disturbance), F03.B3 — Unspecified dementia, moderate, with mood disturbance (moderate, with, mood disturbance), F03.B4 — Unspecified dementia, moderate, with anxiety (moderate, with, anxiety), F03.C0 — Unspecified dementia, severe, without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety (severe), 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), F04 — Amnestic disorder due to known physiological condition (Korsakoff's, Korsakov's, Korsakow's), F06.0 — Psychotic disorder with hallucinations due to known physiological condition (organic, hallucinatory), F06.2 — Psychotic disorder with delusions due to known physiological condition (paranoid, organic), F06.31 — Mood disorder due to known physiological condition with depressive features (transient organic psychotic NEC, depressive type), F06.8 — Other specified mental disorders due to known physiological condition (epileptic), F07.0 — Personality change due to known physiological condition (postleukotomy), F09 — Unspecified mental disorder due to known physiological condition (organic), F10.121 — Alcohol abuse with intoxication delirium (alcoholic, with intoxication, in, abuse), F10.14 — Alcohol abuse with alcohol-induced mood disorder (alcoholic, with, mood disorder, with, abuse), F10.150 — Alcohol abuse with alcohol-induced psychotic disorder with delusions (alcoholic, paranoid type, with, abuse), F10.151 — Alcohol abuse with alcohol-induced psychotic disorder with hallucinations (alcoholic, with, hallucinosis, with, abuse), +339 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.

Blood Glucose Test, Thyroid Stimulating Hormone (TSH)

Contextual Map

Every relationship of F05 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 F05 with these 10 related codes in Claim Check

Hierarchy

Excludes1

Excludes2

Code First

Referenced by Excludes1 notes

Referenced by Excludes2 notes

  • F03 — Unspecified dementia[Excludes2]: “dementia with delirium or acute confusional state (F05)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • F06 — Other mental disorders due to known physiological condition[Excludes2]: “delirium due to known physiological condition (F05)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • F63.1 — Pyromania[Excludes2]: “mental disorders due to known physiological condition (F01-F09)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • F63.2 — Kleptomania[Excludes2]: “stealing in mental disorders due to known physiological condition (F01-F09)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Use Additional Code instructions

Clinical classification (CCSR)

MS-DRG Grouper

  • CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
  • DRG 880 — ACUTE ADJUSTMENT REACTION AND PSYCHOSOCIAL DYSFUNCTION[MS-DRG]: “ACUTE ADJUSTMENT REACTION AND PSYCHOSOCIAL DYSFUNCTION (MDC 19)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

  • MDC 19 — Mental Diseases and Disorders[MDC crossing]: “Mental Diseases and Disorders — 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 · FY2026

Index entries (26)

  • Confusion, confused, acute, with dementia[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Confusion, confused, epileptic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Delirium, delirious (acute or subacute) (not alcohol- or drug-induced), due to (secondary to), general medical condition[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Delirium, delirious (acute or subacute) (not alcohol- or drug-induced), due to (secondary to), multiple etiologies[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Delirium, delirious (acute or subacute) (not alcohol- or drug-induced), postprocedural (postoperative)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Delirium, delirious (acute or subacute) (not alcohol- or drug-induced), puerperal[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Delirium, delirious (acute or subacute) (not alcohol- or drug-induced), with, dementia[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, acute confusional state[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • and 18 more

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 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
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. "F05 — Delirium due to known physiological condition." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/f05-delirium-due-to-known-physiological-condition

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Delirium due to known physiological condition

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.