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

F05 is a billable ICD-10 diagnosis code used to classify Delirium due to known physiological condition in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Mental, Behavioral and Neurodevelopmental disorders (F01-F99).

Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Mental, Behavioral and Neurodevelopmental disorders (F01-F99).

When is it used?

  • May be used when a clinician documents delirium due to known physiological condition in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter
5Mental, Behavioral and Neurodevelopmental disorders (F01-F99)
block
F01-F09Mental disorders due to known physiological conditions
currentF01-F09

Official coding notes

Inclusion terms
  • 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
Applicable to
  • the underlying physiological condition, such as:
  • dementia (F03.9-)
Excludes1 (do not code together)
  • delirium NOS (R41.0)
Excludes2 (may code together if documented)
  • delirium tremens alcohol-induced or unspecified (F10.231, F10.921)
Code first
  • the underlying physiological condition, such as:
  • dementia (F03.9-)

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Coding guidelines

Compatibility

Legacy and official ICD code match exactly.
Legacy codes
F05

Common synonyms

Delirium due to known physiological condition

Frequently asked questions

Code details

CodeF05
SystemICD10
Display nameDelirium due to known physiological condition
ChapterMental, Behavioral and Neurodevelopmental disorders (F01-F99)
BlockMental disorders due to known physiological conditions

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Confusion, confusedDelirium, delirious(acute or subacute) (not alcohol- or drug-induced)Delirium, delirious(acute or subacute) (not alcohol- or drug-induced)Delirium, delirious(acute or subacute) (not alcohol- or drug-induced)Delirium, delirious(acute or subacute) (not alcohol- or drug-induced)Delirium, delirious(acute or subacute) (not alcohol- or drug-induced)Dementia(degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety)Epilepsy, epileptic, epilepsia(attack) (cerebral) (convulsion) (fit) (seizure)Insanity, insanePsychosis, psychoticPsychosis, psychoticPsychosis, psychotic
See also
Dementia

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.

ICD-10 Code F05 for Delirium due to known physiological condition | HealthAssure