Skip to main content
Call AIBook a demo

ICD-10-CM F03.C18: Unspecified dementia, severe, with other behavioral disturbance

F03.C18 is the billable ICD-10-CM code for unspecified dementia, severe, with other behavioral disturbance, in category F03 (Unspecified dementia) of the Mental disorders due to known physiological conditions section. As a principal diagnosis it groups to MS-DRG 884 Organic Disturbances and Intellectual Disability (MDC 19 MDC 19: Mental Diseases and Disorders). It maps to HCC 125 (Dementia, Severe) in CMS-HCC V28. As a secondary diagnosis it is a CC, excluded with 20 principal diagnoses. 13 LCD billing and coding articles list it as covered.

Compiled from CMS files by the QuickIntell RCM Editorial Team · Data effective · Method: reference methodology · Report a data correction

Data currency: ICD-10-CM code descriptions: FY2027 (effective October 1, 2026); IPPS Table 5 (MS-DRG weights): v44 FY2027 (final rule + CN3) (effective October 1, 2026); ICD-10-CM to HCC mapping: PY2027 initial ICD-10-CM mappings (dates of service 2026) (payment year 2027); Medicare Coverage Database billing and coding articles: MCD release October 8, 2026 (effective October 4, 2026). Next CMS release: FY2028 code files, effective October 1, 2027 for the ICD-10-CM code descriptions; FY2028 final rule (August 2027), effective October 1, 2027; an April 1 interim grouper update when CMS issues one for the IPPS Table 5 (MS-DRG weights); PY2028 advance notice (February 2027) and the PY2027 midyear final mapping (spring 2027) for the ICD-10-CM to HCC mapping; weekly, every Thursday for the Medicare Coverage Database billing and coding articles.

Code
F03.C18
billable FY2027 ICD-10-CM code
Category
F03 Unspecified dementia
Chapter
5: Mental, Behavioral and Neurodevelopmental disorders (F01-F99)
CC/MCC (MS-DRG v44)
CC
CMS-HCC V28
HCC 125
POA reporting
Required

Tabular list notes for F03.C18

The tabular list has no notes on F03.C18 itself; the notes below apply from its parent headings.

Inherited from F03 (Unspecified dementia)

Inclusion terms
  • Major neurocognitive disorder NOS
  • Presenile dementia NOS
  • Presenile psychosis NOS
  • Primary degenerative dementia NOS
  • Senile dementia NOS
  • Senile dementia depressed or paranoid type
  • Senile psychosis NOS
Excludes2 (not part of this condition, may be coded together)
  • dementia with delirium or acute confusional state (F05)
  • mild memory disturbance due to known physiological condition (F06.8)

MS-DRG grouping when F03.C18 is the principal diagnosis

MS-DRG v44 groups for F03.C18 as principal diagnosis
MDCMS-DRGs
19 MDC 19: Mental Diseases and Disorders884

The final group also depends on procedures, secondary diagnoses and discharge status; the MS-DRG lookup for F03.C18 shows the full grouping logic.

CC/MCC status and inpatient edits

As a secondary diagnosis, F03.C18 is a CC under MS-DRG v44, unless the principal diagnosis is one of the 20 codes in its exclusion list. Check F03.C18 against a principal diagnosis.

  • Present on admission: a POA indicator is required on inpatient claims.
  • Medicare Code Editor: age conflict: adult diagnosis (age 15 to 124).

CMS-HCC V28 risk adjustment

In the PY2027 mapping, F03.C18 maps to HCC 125 (Dementia, Severe). The HCC lookup shows the RAF weight and the hierarchy.

LCD billing and coding articles that list F03.C18

13 current Medicare billing and coding articles list F03.C18 among the diagnoses that support medical necessity for the services they cover.

For teams evaluating QuickIntell software

Evaluate software for diagnosis coding review

If your team codes diagnoses at volume, review how QuickCode supports qualified coder review of documentation, specificity queries and the billing handoff. Confirm the code sets, settings and reviewer responsibilities during evaluation; a code reference is not a coding determination for a patient.

Evaluate QuickCode for diagnosis codingSee risk adjustment review
Book a software demoAsk about a software workflow

Optional software evaluation, not payer support or help with an individual claim. For coverage or payment decisions, use the official sources on this page. Do not include patient information in a demo booking or inquiry.

Frequently asked questions

What does ICD-10-CM F03.C18 mean?

F03.C18 means unspecified dementia, severe, with other behavioral disturbance. It is one of 24 billable codes under F03, unspecified dementia.

Which MS-DRG does F03.C18 group to?

As the principal diagnosis, F03.C18 groups to MS-DRG 884 Organic Disturbances and Intellectual Disability (MDC 19 MDC 19: Mental Diseases and Disorders) under MS-DRG v44, before procedures and secondary diagnoses are applied.

Does F03.C18 map to an HCC?

Yes: HCC 125, Dementia, Severe, in the PY2027 CMS-HCC V28 mapping.

Is F03.C18 a CC or MCC?

F03.C18 is a CC under MS-DRG v44; 20 principal diagnoses exclude it.

Sources

Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-10. Verify against the primary file before billing or contracting decisions. The reference methodology explains how each figure is computed from these files.

Disclaimer

The descriptor and notes are reproduced from the FY2027 ICD-10-CM files; MS-DRG, CC/MCC and HCC facts come from the CMS FY2027 and PY2027 tables. Code from the medical record and the ICD-10-CM Official Guidelines. Not legal, clinical or billing advice.

Found a figure that does not match the CMS file? Report a data correction with the CMS file and the value you expected; the request reaches the editorial team through the contact form.