Skip to content
HCC Buddy home

HCC Buddy Code Book

Skip to code book content
HCC Buddy
HCC Buddy
Alphabetic Index and Tabular path
HCC Buddy public API, FY2026 Apr updateSource load source requiredSource year 2026Updated 2026-04-01

Index trail

Delirium due to known physiological condition

See Tabular List: F05

F05, Delirium due to known physiological condition

Selected code, source checked for the selected effective period

Commonly confused codes

official source

Not listed for this effective period.

Code details and official notes

F05

Delirium due to known physiological condition

Open the shareable code page for F05→
billable

Includes

official source
  • 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

Excludes 1

official source
  • delirium NOS (R41.0)

Excludes 2

official source
  • delirium tremens alcohol-induced or unspecified (F10.231, F10.921)

Code First

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

Use Additional

official source

Not listed for this effective period.

Code Also

official source

Not listed for this effective period.

7th character

official source

Not listed for this code in the selected Tabular payload.

Placeholder X

official source

Not listed for this code in the selected Tabular payload.

Laterality

official source

No laterality instruction is listed for this code in the selected Tabular payload.

Effective period

source required
  • FY2026 Apr update
  • Source year 2026
  • Updated 2026-04-01
  • HCC Buddy public API
HCC Buddy
HCC Buddy
Alphabetic Index and Tabular path
HCC Buddy public API, FY2026 Apr updateSource load source requiredSource year 2026Updated 2026-04-01

Index trail

Delirium due to known physiological condition

See Tabular List: F05

F05, Delirium due to known physiological condition

Selected code, source checked for the selected effective period

Commonly confused codes

official source

Not listed for this effective period.

Code details and official notes

F05

Delirium due to known physiological condition

Open the shareable code page for F05→
billable

Includes

official source
  • 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

Excludes 1

official source
  • delirium NOS (R41.0)

Excludes 2

official source
  • delirium tremens alcohol-induced or unspecified (F10.231, F10.921)

Code First

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

Use Additional

official source

Not listed for this effective period.

Code Also

official source

Not listed for this effective period.

7th character

official source

Not listed for this code in the selected Tabular payload.

Placeholder X

official source

Not listed for this code in the selected Tabular payload.

Laterality

official source

No laterality instruction is listed for this code in the selected Tabular payload.

Effective period

source required
  • FY2026 Apr update
  • Source year 2026
  • Updated 2026-04-01
  • HCC Buddy public API
HCC Buddy Insights

HCC Mapping

V28 source requiredV24 source requiredRxHCC source requiredESRD/PACE source requiredHHS-HCC source required or member context needed for selected effective period (HHS-HCC)

RAF Value

V28 RAF source requiredV24 RAF source requiredRxHCC RAF source requiredESRD/PACE RAF source requiredHHS-HCC RAF source required

Model Period

FY2026 Apr update

Source

source required

Audit Caution

Close codes need documentation support before selection. Do not assume relationships.
Reviewed by the HCC Buddy Coding Team

HCC Buddy workflow band

HCC mapping, RAF, MEAT, source trail, and audit caution stay in view.

MEAT supportaudit cautionsource required

HHS-HCC

source required

HHS-HCC source required or member context needed for selected effective period

RAF: source required

MEAT checklist

Reviewed by the HCC Buddy Coding Team

Monitor, Evaluate, Assess, or Treat must be supported in the provider note.

HCC Buddy guidance, not official ICD-10-CM text.

Audit caution

Reviewed by the HCC Buddy Coding Team

Close codes need documentation support before selection. Do not assume relationships.

HCC Buddy guidance, not official ICD-10-CM text.

Reviewer sign-off

Reviewed by the HCC Buddy Coding Team

MEAT, documentation support, audit cautions, and close-code guidance are reviewed and approved for this effective period.

HCC Buddy enrichment is separate from official source text.

Last updated: April 1, 2026 · Not a substitute for official coding guidelines. No PHI or patient data.
HCC Buddy Code Card
FY 2026 Apr update
F05Billable

Delirium due to known physiological condition

ACA/HHS

Source required

RAF source required

Reviewed by the HCC Buddy Coding TeamFY2026 Apr update

Code

F05

V28 HCC

Not mapped

RAF

source required

Compare tray

Add close codes to compare documentation differences.