Alphabetic Index FY2027

F02.C4

Dementia in other diseases classified elsewhere, severe, with anxiety

FY2027Chapter 5: Mental, Behavioral and Neurodevelopmental disorders/F01–F09 Mental disorders due to known physiological conditions

BillableComplete code, valid to report
Care settingsHospice: not accepted as primaryHospital CCIPF Primary · MS-DRG 884

F02.C4 (also written F02C4) is a billable ICD-10-CM diagnosis code for dementia in other diseases classified elsewhere, severe, with anxiety. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 24 codes in category F02 (Dementia in other diseases classified elsewhere). The Alphabetic Index lists it under 1 entry. Its coding notes include a Code first instruction, 1 Excludes1 entry and 3 Excludes2 entries.

Guidelines tip

From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.

Dementia codes depend on severity documented by the provider. If severity is not documented, the unspecified severity code is assigned. If severity progresses during an inpatient stay, one code is assigned for the highest level.

Guidelines I.C.5.dDementia: severityRead the official text

Code first

If the underlying condition listed here is present and known, sequence it first.

Inherited from F02 Dementia in other diseases classified elsewhere
  • the underlying physiological condition, such as:
    • Alzheimer's (G30.-)
    • cerebral lipidosis (E75.4)
    • Creutzfeldt-Jakob disease (A81.0-)
    • epilepsy and recurrent seizures (G40.-)
    • hepatolenticular degeneration (E83.01)
    • human immunodeficiency virus [HIV] disease (B20)
    • Huntington's disease (G10)
    • hypercalcemia (E83.52)
    • hypothyroidism, acquired (E00-E03.-)
    • intoxications (T36-T65)
    • Jakob-Creutzfeldt disease (A81.0-)
    • multiple sclerosis (G35-)
    • neurocognitive disorder with Lewy bodies (G31.83)
    • neurosyphilis (A52.17)
    • niacin deficiency [pellagra] (E52)
    • other frontotemporal neurocognitive disorder (G31.09)
    • Parkinson's disease (G20.-)
    • Pick's disease (G31.01)
    • polyarteritis nodosa (M30.0)
    • prion disease (A81.9)
    • systemic lupus erythematosus (M32.-)
    • traumatic brain injury (S06.-)
    • trypanosomiasis (B56.-, B57.-)
    • vitamin B deficiency (E53.8)

Excludes1

Not coded here. The listed conditions generally should not be reported together.

Inherited from F02 Dementia in other diseases classified elsewhere
  • mild neurocognitive disorder due to known physiological condition with or without behavioral disturbance (F06.7-)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Inherited from F02 Dementia in other diseases classified elsewhere
Also from chapter/block level (1 note)
Inherited from Chapter 5 Mental, Behavioral and Neurodevelopmental disorders
  • symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

Hospice: not accepted as primary

Not accepted as the principal diagnosis on a hospice claim (bill types 081x and 082x). The Integrated OCE returns an edit for this code.
Reason: Manifestation code. Report the underlying condition first (see the Code first note). Supplementary or additional code, not allowed as principal diagnosis.

Source: CMS Integrated Outpatient Code Editor (IOCE) v27.3, effective October 1, 2026, edits 86 and 113

Hospital CC

Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 20 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.

Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix C

IPF Primary

IPF MS-DRG adjustment. A principal diagnosis of this code groups to this MS-DRG:

MS-DRGDescriptionFactor
884Organic disturbances & intellectual disabilities1.08
A principal diagnosis that groups to none of the 19 designated MS-DRGs gets no MS-DRG adjustment. Otherwise the claim still receives the federal per diem base rate and the other adjustments. This code carries a Code first note (see the Code first note). Under CMS’s IPF grouper rules, when a psychiatric code carries a Code first note, the provider follows the instructions in the Tabular List, and the grouper identifies the principal diagnosis as non-psychiatric and searches the secondary codes for a psychiatric code.

Source: CMS IPF PPS FY 2027 final rule (CMS-1847-F), Addendum A; code lists from the CMS MS-DRG Definitions Manual v44, Addendum B-2 (Code First table); effective for discharges on or after October 1, 2026

Includes

Further defines or gives examples of the content of the category.

Inherited from F02 Dementia in other diseases classified elsewhere
  • Major neurocognitive disorder in other diseases classified elsewhere
Also from chapter/block level (1 note)
Inherited from Chapter 5 Mental, Behavioral and Neurodevelopmental disorders
  • disorders of psychological development

Inclusion terms

Conditions classified to this code.

This code
  • Major neurocognitive disorder in other diseases classified elsewhere, severe, with anxiety

Notes

Also from chapter/block level (1 note)
Inherited from F01–F09 Mental disorders due to known physiological conditions
  • This block comprises a range of mental disorders grouped together on the basis of their having in common a demonstrable etiology in cerebral disease, brain injury, or other insult leading to cerebral dysfunction. The dysfunction may be primary, as in diseases, injuries, and insults that affect the brain directly and selectively; or secondary, as in systemic diseases and disorders that attack the brain only as one of the multiple organs or systems of the body that are involved.

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 1 entry