F02.80

🧬 ICD-10-CM F02.80 — Dementia in Other Diseases Classified Elsewhere, Unspecified Severity, Without Behavioral Disturbance, Psychotic Disturbance, Mood Disturbance, and Anxiety

Billable Code Confirmed

ICD-10-CM F02.80 is a valid, billable 5-character ICD-10-CM code for FY2026. All five characters are present: F02 (category) + .8 (unspecified severity) + 0 (without behavioral, psychotic, mood, or anxiety disturbance). No 7th character is required. This code is ALWAYS sequenced second — it is a mandatory manifestation code and must never appear as the principal or first-listed diagnosis.

Non-Billable Parent Codes — Never Submit These

• ❌ F02 — 3-character category header — non-billable
• ❌ F02.8 — 4-character subcategory header — missing disturbance specifier

Always submit F02.80 (all 5 characters) when dementia of unspecified severity without any documented behavioral, psychotic, mood, or anxiety disturbance is present in the context of another underlying physiological condition.

Clinical Context: F02.80 Is ALWAYS Sequenced Second

F02.80 operates under the etiology/manifestation coding convention — one of the most fundamental sequencing rules in ICD-10-CM. The underlying physiological condition (e.g., G30.9 Alzheimer’s disease, G20.A1 Parkinson’s disease, G10 Huntington’s disease) is ALWAYS sequenced first, with F02.80 as the mandatory secondary code. The ICD-10-CM Alphabetic Index displays F02.80 in slanted brackets [F02.80] when indexed under the underlying condition — slanted brackets are the ICD-10-CM visual signal that a code is a mandatory manifestation that cannot be a principal diagnosis.

Code Classification

ICD-10-CM Diagnosis Code — Manifestation code under the etiology/manifestation convention. For associated inpatient procedure coding, see the ICD-10-PCS Crosswalk section below.

---

🔍 Code Description

ICD-10-CM F02.80 classifies dementia — defined in current ICD-10-CM/DSM-5 aligned terminology as Major Neurocognitive Disorder (MNCD) — occurring as a direct manifestation of another physiological condition classified elsewhere in ICD-10-CM, at an unspecified level of severity, and without documented behavioral disturbance, psychotic symptoms, mood disturbance, or anxiety.

The “without disturbance” qualifier of F02.80 is defined by the absence of all four of the following specific neuropsychiatric features:

• Behavioral disturbance (agitation, aggression, wandering, disinhibition, sexual behavior disturbance) — if present → F02.81
• Psychotic disturbance (hallucinations, delusions) — if present → F02.82
• Mood disturbance (depressed mood, emotional lability, euphoria) — if present → F02.83
• Anxiety (generalized anxiety, phobias, OCD-spectrum symptoms in context of dementia) — if present → F02.84

The “unspecified severity” qualifier of the F02.80 group reflects that the F02.8x codes are used when severity is not further documented. Under the FY2026 ICD-10-CM tabular expansion, severity-specific subcategories exist: F02.Ax = mild, F02.Bx = moderate, F02.Cx = severe — each with their own “without/with behavioral disturbance” decimal extensions. Because F02.80 does not specify severity, it maps to CMS-HCC v28 HCC 127 (mild or unspecified dementia) rather than the higher-weighted HCC 126 (moderate) or HCC 125 (severe). Documenting dementia severity is a significant CDI and risk adjustment opportunity under the fully phased-in v28 model.

---

🌳 Code Tree / Hierarchy

F01-F09 Mental Disorders Due to Known Physiological Conditions  
│  
├── F02 — Dementia in Other Diseases Classified Elsewhere ❌ Non-billable  
│ │ [Includes: Major neurocognitive disorder in other diseases classified elsewhere]  
│ │ [Code FIRST the underlying physiological condition]  
│ │  
│ ├── F02.8 — Dementia in Other Diseases, Unspecified Severity ❌ Non-billable  
│ │ │  
│ │ ├── F02.80 — Without behavioral, psychotic, mood, or anxiety disturbance ◀ THIS CODE ✅ Billable  
│ │ ├── F02.81 — With behavioral disturbance ✅ Billable  
│ │ ├── F02.82 — With psychotic disturbance ✅ Billable  
│ │ ├── F02.83 — With mood disturbance ✅ Billable  
│ │ └── F02.84 — With anxiety ✅ Billable  
│ │  
│ ├── F02.A — Dementia in Other Diseases, Mild Severity ❌ Non-billable  
│ │ ├── F02.A0 — Without disturbance ✅ Billable → HCC 127  
│ │ ├── F02.A1 — With behavioral disturbance ✅ Billable → HCC 127  
│ │ ├── F02.A2 — With psychotic disturbance ✅ Billable → HCC 127  
│ │ ├── F02.A3 — With mood disturbance ✅ Billable → HCC 127  
│ │ └── F02.A4 — With anxiety ✅ Billable → HCC 127  
│ │  
│ ├── F02.B — Dementia in Other Diseases, Moderate Severity ❌ Non-billable  
│ │ ├── F02.B0 — Without disturbance ✅ Billable → HCC 126  
│ │ ├── F02.B1 — With behavioral disturbance ✅ Billable → HCC 126  
│ │ ├── F02.B2 — With psychotic disturbance ✅ Billable → HCC 126  
│ │ ├── F02.B3 — With mood disturbance ✅ Billable → HCC 126  
│ │ └── F02.B4 — With anxiety ✅ Billable → HCC 126  
│ │  
│ └── F02.C — Dementia in Other Diseases, Severe Severity ❌ Non-billable  
│ ├── F02.C0 — Without disturbance ✅ Billable → HCC 125  
│ ├── F02.C1 — With behavioral disturbance ✅ Billable → HCC 125  
│ ├── F02.C2 — With psychotic disturbance ✅ Billable → HCC 125  
│ ├── F02.C3 — With mood disturbance ✅ Billable → HCC 125  
│ └── F02.C4 — With anxiety ✅ Billable → HCC 125

Upgrade Severity When Documented

F02.80 (unspecified severity) should only be used when the physician has not documented severity of dementia. If documentation supports mild → use F02.A0; moderate → F02.B0; severe → F02.C0. Severity documentation directly drives a higher HCC tier under CMS-HCC v28 — a meaningful CDI query opportunity at every dementia-related encounter.

---

✅ Includes

The following clinical terms and scenarios map to F02.80 when the underlying physiological condition is coded first and no behavioral, psychotic, mood, or anxiety disturbance is documented:

• Dementia in Alzheimer’s disease NOS, without behavioral disturbance (with G30.9 first)
• Dementia in Parkinson’s disease NOS, without behavioral disturbance (with G20.A1 / G20.B1 / G20.C1 first)
• Dementia in Huntington’s disease, without behavioral disturbance (with G10 first)
• Dementia in frontotemporal neurocognitive disorder, without behavioral disturbance (with G31.09 first)
• Major neurocognitive disorder in other diseases classified elsewhere, unspecified severity, no disturbance
• Secondary dementia NOS, without behavioral disturbance

The DSM-5 / DSM-5-TR term “Major Neurocognitive Disorder” (MNCD) is the official diagnostic counterpart to ICD-10-CM’s “dementia in other diseases classified elsewhere” — both index to the F02.x family. The ICD-10-CM includes note under F02 explicitly states: “Includes: Major neurocognitive disorder in other diseases classified elsewhere.”

---

❌ Excludes

Excludes 1 — Cannot Be Coded Simultaneously with F02.80

Code	Description	Note
F06.7-	Mild neurocognitive disorder due to known physiological condition	Mutually exclusive — mild NCD is a DSM-5 distinct entity representing sub-threshold cognitive decline that does NOT meet full dementia/MNCD criteria; if mild NCD is documented, use F06.7x, NOT F02.80 — they cannot coexist on the same claim

Excludes 1 Violation Risk

F06.70 / F06.71 (mild neurocognitive disorder due to known physiological condition) carries an Excludes 1 instruction relative to F02. These are mutually exclusive — mild NCD (sub-threshold, does not meet full dementia criteria) and dementia/major NCD cannot be assigned simultaneously. If documentation is ambiguous — “cognitive impairment” vs. “dementia” — a CDI query is warranted to establish whether the diagnosis meets full major NCD/dementia criteria or represents only mild NCD.

Excludes 2 — May Be Coded in Addition if Separately Present

Code	Description	Note
F10-F19 (with .17, .27, .97)	Dementia in alcohol and psychoactive substance disorders	Excludes 2 — substance-induced dementia is coded within the substance use disorder category; both may coexist if separately documented and distinct
F01.5-, F01.A-, F01.B-, F01.C-	Vascular dementia	Excludes 2 — vascular dementia is separately classified; if a patient has both Alzheimer’s dementia AND vascular dementia, both F02.x and F01.5x/F01.Ax/F01.Bx/F01.Cx may be coded when explicitly documented

Excludes 2 — Not Mutually Exclusive

Vascular dementia (F01.5x and severity-specific variants) is Excludes 2 from F02. If a patient has documented mixed dementia — both Alzheimer’s and vascular components — both the F02.x and F01.x codes may be reported when the physician explicitly documents both conditions as separately present.

---

📋 Clinical Overview

The Etiology/Manifestation Convention — The Most Critical Rule

The etiology/manifestation coding convention is the foundational sequencing rule governing ALL F02.x codes. Understanding it is non-negotiable for accurate coding and DRG assignment.

Element	Description
Etiology code	The underlying physiological disease causing the dementia — sequences FIRST; examples: G30.9 (Alzheimer’s), G20.A1 (Parkinson’s), G10 (Huntington’s)
Manifestation code	F02.80 — the dementia itself as a secondary expression of the underlying disease — sequences SECOND
ICD-10-CM visual signal	In the Alphabetic Index, manifestation codes appear in slanted brackets [F02.80] — slanted brackets = mandatory second code, never principal
Sequencing rule	The underlying etiology always sequences as principal/first-listed; F02.80 always sequences as the secondary/additional code
Consequence of reversal	Sequencing F02.80 as principal is a guideline violation — it will misrepresent the reason for admission, potentially misgroup the DRG, and trigger coding compliance risk

CDI Query Trigger — Severity Specification

The single highest-impact CDI query for every F02.80 encounter is: “Please document the severity of the patient’s dementia as mild, moderate, or severe.” Under CMS-HCC v28 (fully phased in at 100% for 2026), unspecified severity maps to HCC 127 (RAF ~0.341); moderate maps to HCC 126 (higher RAF); severe maps to HCC 125 (highest RAF). Severity documentation costs nothing but five words in the assessment — and directly drives risk adjustment accuracy for Medicare Advantage patients.

Behavioral Disturbance Subcodes — The Critical Decimal Distinction

Selecting the correct F02.8x decimal is as important as the severity tier. All five behavioral disturbance subcategories share the same 4-character parent (F02.8) but differ critically in their 5th character — and their clinical and billing implications.

Code	Disturbance Type	Clinical Indicators	HCC v28
F02.80	None documented	No agitation, no psychosis, no mood disturbance, no anxiety	HCC 127
F02.81	Behavioral	Agitation, aggression, wandering, disinhibition, sexually inappropriate behavior	HCC 127
F02.82	Psychotic	Hallucinations (visual > auditory in dementia), delusions, paranoia	HCC 127
F02.83	Mood	Depressed mood, emotional lability, apathy, euphoria in context of dementia	HCC 127
F02.84	Anxiety	Anxiety, fearfulness, OCD-spectrum symptoms arising in context of dementia	HCC 127

All Five F02.8x Codes Map to HCC 127 Under v28

Under CMS-HCC v28, ALL five F02.8x subcodes (F02.80 through F02.84) map to HCC 127 — the disturbance specifier does not differentiate HCC tier within the unspecified severity group. However, the disturbance specifier is still clinically and documentation-integrity critical: it drives care plan specificity, medication appropriateness review, quality metrics, and accreditation standards — and becomes highly relevant when the severity-specific codes (F02.Ax, F02.Bx, F02.Cx) are used, where HCC tier differs by severity.

Pathophysiology

Dementia classified under F02.80 represents major neurocognitive disorder arising as a direct neuropathological consequence of a separate underlying disease process. Unlike Alzheimer’s disease (which is itself a primary neurodegenerative disease driving dementia), the F02 category captures dementia as a secondary manifestation — the brain damage responsible for the cognitive decline is downstream of another primary pathological process: amyloid/tau pathology (Alzheimer’s), alpha-synuclein aggregation (Parkinson’s, Lewy body), polyglutamine expansion (Huntington’s), prion misfolding (CJD), vascular injury (cerebrovascular disease, coded to F01.x), metabolic toxicity (Wilson’s, pellagra, hypothyroidism), or systemic immune/inflammatory disease (HIV, SLE, multiple sclerosis). The cognitive impairment meets major NCD criteria: significant decline in one or more cognitive domains (complex attention, executive function, learning/memory, language, perceptual-motor, or social cognition) that is sufficient to interfere with independence in everyday activities and is not exclusively explained by delirium or another mental disorder.

Documentation Requirements

For accurate assignment of F02.80, physician documentation should include:

1. Explicit dementia diagnosis — “dementia,” “major neurocognitive disorder,” or equivalent physician-level documentation; “cognitive impairment” alone is not sufficient for F02.80
2. Underlying disease identified and documented — the etiology must be specified (e.g., “dementia due to Alzheimer’s disease,” “Parkinson’s disease dementia”) to enable both codes in the mandatory pair
3. Severity — mild, moderate, severe, or unspecified; severity documentation enables upgrade from F02.80 (HCC 127) to F02.Ax/Bx/Cx tiers
4. Presence or absence of behavioral, psychotic, mood, or anxiety disturbance — determines the correct 5th-character decimal; absence must be documented or inferable; presence requires the appropriate F02.81/82/83/84
5. Active management — dementia must be affecting patient management at the encounter to justify coding per UHDDS “other diagnoses” criteria (inpatient) or first-listed/secondary code selection (outpatient)

---

💰 HCC Risk Adjustment (CMS-HCC v28)

Field	Detail
CMS-HCC Model Version	v28 (100% Implementation FY2026)
HCC Assignment	✅ Mapped — HCC 127
HCC Category Name	Mild or Unspecified Dementia
RAF Coefficient (Community Non-Dual Aged)	~0.341
Severity Upgrade Path	F02.Bx → HCC 126 (Moderate Dementia); F02.Cx → HCC 125 (Severe Dementia)
RxHCC Assignment	Review current RxHCC mapping tables

F02.80 maps to CMS-HCC v28 HCC 127 (Mild or Unspecified Dementia), contributing a RAF coefficient of approximately 0.341 for community non-dual aged beneficiaries. This represents a restructuring from the prior v24 model where dementia was either “complicated” (HCC 52) or “uncomplicated” (HCC 51).

V28 Is Fully Phased In at 100% for 2026

The transition from CMS-HCC v24 to v28 is complete for FY2026 — organizations are now operating at 100% v28 (v24 is no longer blended into the calculation). The v28 dementia tier structure (HCC 125/126/127 by severity) makes severity documentation the single most impactful CDI opportunity in dementia coding. F02.80 (unspecified severity → HCC 127) carries a lower RAF than F02.Bx (moderate → HCC 126) or F02.Cx (severe → HCC 125). Every encounter where dementia severity is documentable but undocumented represents a missed risk adjustment opportunity.

Additionally, capture all RAF-bearing comorbidities present at each F02.80 encounter:

• Parkinson’s disease (G20.A1 / G20.B1 / G20.C1) — HCC-mapped under v28
• HIV disease (B20) — HCC 1 (v28), very high RAF coefficient
• Heart failure (I50.9) — HCC 226 or related
• Diabetes with complications — HCC 37/38 series
• Malnutrition — review for HCC mapping; common in advanced dementia

---

🏥 MS-DRG Assignment

MDC 19 — Mental Diseases and Disorders (when F02.80 is principal — which should RARELY occur)

DRG	Title	Est. Relative Weight*
DRG 880	Acute Adjustment Reaction and Psychosocial Dysfunction	~0.80-1.10
DRG 881	Depressive Neuroses	~0.60-0.85
DRG 882	Neuroses Except Depressive	~0.50-0.75

*Approximate. Verify against IPPS FY2026 Final Rule tables.

Warning

F02.80 Grouped to MDC of the Underlying Disease When Sequenced Correctly In the overwhelming majority of inpatient cases, F02.80 is sequenced second and the underlying disease drives MDC assignment. Alzheimer’s disease (G30.9) as principal → MDC 01 (Nervous System) → DRG 056 (Degenerative Nervous System Disorders with MCC) / DRG 057 (with CC) / DRG 058 (without CC/MCC). Parkinson’s disease (G20.x) as principal → MDC 01. HIV (B20) as principal → MDC 25 (HIV/AIDS). Only in the rare scenario where no underlying disease is identified and F02.80 is sequenced first does the encounter group to MDC 19 — and even then, a CDI query should be initiated to identify the etiology before finalizing the principal diagnosis.

---

🔗 Related ICD-10-CM Codes

Behavioral Disturbance Variants — Unspecified Severity (F02.8x)

Code	Description
F02.80	Without behavioral, psychotic, mood, or anxiety disturbance ← This Code
F02.81	With behavioral disturbance (agitation, aggression, wandering, disinhibition)
F02.82	With psychotic disturbance (hallucinations, delusions)
F02.83	With mood disturbance (depressed affect, emotional lability)
F02.84	With anxiety

Severity-Specific Codes — “Without Disturbance” Column (F02.x0)

Code	Description	HCC v28
F02.80	Unspecified severity, without disturbance ← This Code	HCC 127
F02.A0	Mild severity, without disturbance	HCC 127
F02.B0	Moderate severity, without disturbance	HCC 126
F02.C0	Severe severity, without disturbance	HCC 125

Contrast — Alzheimer’s Disease Codes (Etiology — Sequences FIRST)

Code	Description
G30.0	Alzheimer’s disease with early onset (< age 65)
G30.1	Alzheimer’s disease with late onset (≥ age 65)
G30.8	Other Alzheimer’s disease
G30.9	Alzheimer’s disease, unspecified — the most commonly paired etiology with F02.80

Contrast — Parkinson’s Disease Codes (Etiology — Sequences FIRST)

Code	Description
G20.A1	Parkinson’s disease without dyskinesia, without mention of fluctuations
G20.A2	Parkinson’s disease without dyskinesia, with fluctuations
G20.B1	Parkinson’s disease with dyskinesia, without mention of fluctuations
G20.B2	Parkinson’s disease with dyskinesia, with fluctuations
G20.C1	Parkinsonism, unspecified

Other Common Etiology Codes (Sequences FIRST with F02.80)

Code	Description
G10	Huntington’s disease
G31.09	Other frontotemporal dementia (behavioral variant FTD, semantic dementia, progressive nonfluent aphasia)
G35.D	Multiple sclerosis
A81.00	Creutzfeldt-Jakob disease, unspecified (prion disease)
B20	HIV disease (sequences as principal in HIV-related admissions — shifts to MDC 25)
E83.01	Wilson’s disease (hepatolenticular degeneration)
E53.8	Other specified B group vitamin deficiencies (B12 deficiency dementia)

Contrast — Vascular Dementia (Excludes 2 — Separate Code Family)

Code	Description
F01.50	Vascular dementia, unspecified severity, without disturbance
F01.51	Vascular dementia, unspecified severity, with behavioral disturbance
F01.A0	Vascular dementia, mild, without disturbance
F01.B0	Vascular dementia, moderate, without disturbance
F01.C0	Vascular dementia, severe, without disturbance

Related Behavioral Health and Neurological Codes

Code	Description	Coding Relevance
F06.70	Mild neurocognitive disorder due to known physiological condition, without behavioral disturbance	Excludes 1 from F02 — use when cognitive decline is documented but does NOT meet full dementia/MNCD criteria; mutually exclusive with F02.80
F06.71	Mild neurocognitive disorder due to known physiological condition, with behavioral disturbance	Excludes 1 from F02; query physician to distinguish mild NCD vs. major NCD (dementia) when documentation is ambiguous
Z91.83	Wandering in diseases classified elsewhere	Code additionally when wandering is documented — a critical safety and care planning code; commonly paired with F02.81 (behavioral disturbance) but may accompany any dementia code
R41.3	Other amnesia	Use when memory loss is documented as a symptom without a confirmed dementia diagnosis — do not default to F02.80 for undifferentiated memory complaints
F05	Delirium due to known physiological condition	Important differential — delirium superimposed on dementia is common; delirium is NOT included in F02.80; code F05 additionally when delirium is separately documented and distinct from the chronic dementia
Z87.39	Personal history of other endocrine, nutritional and metabolic diseases	May be applicable if resolved metabolic etiology remains relevant to history

---

🛠️ Commonly Associated CPT Codes (Neurology/Geriatrics)

Outpatient and Physician Setting Context

The CPT codes below are associated with the cognitive evaluation, diagnosis, and ongoing management of dementia in the outpatient and physician fee schedule settings. In the inpatient setting, ICD-10-PCS procedure codes govern procedural reporting.

CPT Code	Description	Clinical Application
99483	Assessment of and care planning for a patient with cognitive impairment, including all required elements	The dedicated dementia assessment and care plan code — requires 9 specific elements including independent historian, functional assessment, standardized staging instruments (CDR, FAST), medication reconciliation, neuropsychiatric symptom evaluation, safety assessment, caregiver needs assessment, and advance directive review; may only be billed with a dementia-related ICD-10 code; cannot be billed same DOS as standard E/M by same provider without modifier -25
96132	Neuropsychological testing evaluation services by physician or other qualified health care professional, including integration of patient data, interpretation of standardized test results and clinical data, clinical decision-making, treatment planning and report, and interactive feedback to patient, family member(s) or caregiver(s), when performed; first hour	Comprehensive neuropsychological battery — standard for formal dementia severity staging and differential diagnosis; report for the first hour of evaluation/interpretation services
96133	+Neuropsychological testing evaluation services; each additional hour	Add-on for each additional hour of neuropsychological test evaluation beyond the first; never alone
96136	Psychological or neuropsychological test administration and scoring by physician or other qualified health care professional, two or more tests, first 30 minutes	Test administration component — report separately from 96132 when test administration and interpretation are performed by the same provider
96137	+Psychological or neuropsychological test administration and scoring, each additional 30 minutes	Add-on for additional test administration time; never alone
96116	Neurobehavioral status exam (clinical assessment of thinking, reasoning and judgment, acquired knowledge, attention, language, memory, planning and problem solving, and visual-spatial abilities), by physician or other qualified health care professional, with interpretation and report; first hour	Neurobehavioral status exam — less comprehensive than 96132; used for office-based cognitive screening with interpretation; first hour
96121	+Neurobehavioral status exam, each additional hour	Add-on for 96116; never alone
99213	Office or other outpatient visit, established patient, low MDC	Routine follow-up for stable dementia management — when 99483 is not performed; append modifier -25 if performed same DOS as a procedure
99214	Office or other outpatient visit, established patient, moderate MDC	More complex dementia follow-up with medication management, caregiver counseling, behavioral symptom management

NCCI Bundling Considerations

NCCI PTP Edits — Verify Before Billing

• 99483 and a same-day E/M (99213/99214): Modifier -25 must be appended to the E/M when both are performed on the same date and the E/M is separately documentable and identifiable beyond the dementia assessment itself.
• 96132 (neuropsychological testing evaluation) and 96116 (neurobehavioral status exam) billed same DOS: review current NCCI PTP edit status; these represent distinct service types but payer policies vary on same-day billing.
• 96136/96137 (test administration) and 96132/96133 (evaluation/interpretation): may be reported together when administration and evaluation/interpretation are both performed by the same qualified provider on the same date — verify documentation supports both components.
• 99483 and 96132 same DOS by the same provider: generally not billable together as both involve cognitive assessment; if a separate neuropsychological battery was ordered and interpreted on the same day, document clearly that each service was distinct.

---

🔬 ICD-10-PCS Crosswalk (Inpatient Procedures)

When F02.80 is an inpatient diagnosis and a mental health or neurological procedure is performed, the following ICD-10-PCS sections and root operations are relevant. Full PCS codes require completion of all seven characters — consult the PCS tables for the applicable fiscal year.

PCS Section	Body System / Type	Root Operation	Clinical Application
G (Mental Health)	Z (None)	3 (Psychological Tests)	GZ3ZZZZ — Psychological testing / neuropsychological assessment for dementia staging; formally documents cognitive assessment in inpatient setting
G (Mental Health)	Z (None)	1 (Psychological Counseling)	GZ1ZZZZ — Mental health counseling for patient and/or family regarding dementia care planning
G (Mental Health)	Z (None)	2 (Crisis Intervention)	GZ2ZZZZ — Crisis intervention when behavioral decompensation occurs (relevant for F02.81 encounters; less applicable to F02.80 without disturbance)

---

💊 Coding Scenarios and Examples

---

Scenario 1 — Alzheimer’s Disease Dementia, Unspecified Severity, Without Behavioral Disturbance (Outpatient)

Clinical Vignette: A 78-year-old female with known late-onset Alzheimer’s disease presents for annual cognitive assessment. Her caregiver reports gradual memory decline over the past year — she forgets appointments and repeats questions but remains calm, with no aggression, hallucinations, or mood changes. MMSE score 18/30. Physician documents: “Alzheimer’s disease dementia, no behavioral disturbance, unspecified severity.” Medication reconciliation performed; advance care plan updated.

CPT Codes (Outpatient/Physician):

• 99483 — Cognitive assessment and care plan, all 9 elements documented

ICD-10-CM:

• G30.1 — Alzheimer’s disease with late onset (etiology — sequences FIRST)
• F02.80 — Dementia in other diseases classified elsewhere, unspecified severity, without behavioral disturbance (manifestation — sequences SECOND)

CDI Opportunity — Severity Query

Physician documents “unspecified severity” — MMSE of 18/30 is consistent with moderate Alzheimer’s dementia (MMSE 10-19). A brief query asking the physician to document severity as mild, moderate, or severe could upgrade F02.80 (HCC 127) to F02.B0 (moderate, HCC 126) — a meaningful RAF improvement under v28.

---

Scenario 2 — Parkinson’s Disease Dementia, Without Behavioral Disturbance (Inpatient Admission)

Clinical Vignette: A 72-year-old male with established Parkinson’s disease dementia is admitted for urinary tract infection and dehydration. Cognitive assessment during admission confirms significant dementia — he cannot perform IADLs independently. No agitation, no hallucinations documented. Physician documents: “Parkinson’s disease with dementia, no behavioral disturbance.”

Principal Diagnosis:

• G20.A1 — Parkinson’s disease without dyskinesia, without mention of fluctuations (etiology — mandatory principal; etiology/manifestation convention)

Additional Diagnoses:

• F02.80 — Dementia in other diseases classified elsewhere, unspecified severity, without behavioral disturbance (manifestation — mandatory second code)
• N39.0 — Urinary tract infection, site not specified (complicating condition)
• E86.0 — Dehydration (complicating condition)

MS-DRG Assignment:

• Groups to MDC 01 (Diseases and Disorders of the Nervous System) based on G20.A1 as principal, NOT MDC 19

Sequencing Critical — G20.x ALWAYS First

Even when the dementia is the primary focus of care planning and management, the etiology/manifestation convention requires G20.A1 to sequence as principal and F02.80 to sequence as secondary. Placing F02.80 first misrepresents the encounter, violates ICD-10-CM Official Guidelines, and may misgroup the DRG.

---

Scenario 3 — Huntington’s Disease Dementia, Unspecified Severity, Without Behavioral Disturbance (Outpatient)

Clinical Vignette: A 55-year-old male with known Huntington’s disease presents to neurology for cognitive follow-up. Documented: progressive cognitive decline meeting dementia criteria, no psychosis, no mood disturbance, no behavioral symptoms. Neuropsychological testing ordered.

CPT Codes:

• 99214 — Office visit, established patient, moderate MDC
• 96132 — Neuropsychological testing evaluation, first hour
• 96136 — Neuropsychological test administration, first 30 minutes

ICD-10-CM:

• G10 — Huntington’s disease (etiology — sequences FIRST)
• F02.80 — Dementia in other diseases classified elsewhere, unspecified severity, without behavioral disturbance (manifestation — sequences SECOND)

---

Scenario 4 — HIV-Associated Dementia, Without Behavioral Disturbance (Inpatient)

Clinical Vignette: A 48-year-old male with AIDS (CD4 22) is admitted with acute respiratory failure. He has documented HIV-associated dementia — cognitive decline to major NCD level, no behavioral disturbance. Admission is for the respiratory failure.

Principal Diagnosis:

• B20 — Human immunodeficiency virus (HIV) disease (per ICD-10-CM Official Guidelines Section I.C.1.a.2 — B20 sequences as principal when an HIV patient is admitted for any HIV-related condition; groups to MDC 25)

Additional Diagnoses:

• F02.80 — Dementia in other diseases classified elsewhere, without behavioral disturbance (manifestation — second)
• J96.01 — Acute respiratory failure with hypoxia (reason for admission — additional)

MDC Override — B20 as Principal Shifts to MDC 25

Assigning B20 as principal moves the encounter to MDC 25 (HIV/AIDS) — not MDC 01 or MDC 19. Never sequence F02.80 or another condition as principal in an HIV-related admission when HIV is identified.

---

⚠️ Coding Pitfalls and Tips

	Pitfall or Tip
❌	Never sequence F02.80 as the principal or first-listed diagnosis — it is a mandatory manifestation code; the underlying physiological etiology (G30.x, G20.x, G10, etc.) always sequences first per the etiology/manifestation convention
❌	Do not use F02.80 when severity is documented — mild → F02.A0; moderate → F02.B0; severe → F02.C0; using F02.80 when severity is charted represents a specificity failure with direct HCC impact under v28
❌	Do not code F02.80 simultaneously with F06.70 — this is an Excludes 1 violation; mild NCD (sub-threshold, does not impair independence) and major NCD/dementia (impairs independence) are mutually exclusive; query the physician when documentation is ambiguous
❌	Do not use F02.80 for vascular dementia — vascular dementia is coded to F01.50 and the F01.x family; F02.x is reserved for non-vascular secondary dementias
❌	Do not use F02.80 as a standalone code — it is never valid alone; the underlying physiological disease code MUST always accompany it
❌	Do not confuse delirium with dementia — delirium (F05) superimposed on dementia is common but represents a separate code; delirium is NOT included within F02.80; code F05 additionally when the physician separately documents acute delirium
✅	Always query for dementia severity — documenting mild/moderate/severe at every dementia encounter is the single highest-impact v28 HCC CDI action; F02.80 (unspecified/HCC 127) vs. F02.B0 (moderate/HCC 126) vs. F02.C0 (severe/HCC 125) represents meaningful RAF differentiation
✅	Query for behavioral, psychotic, mood, or anxiety disturbances — if any disturbance is present but undocumented, an appropriate query can upgrade F02.80 to F02.81/82/83/84, improving clinical documentation accuracy and care plan completeness
✅	Code Z91.83 (wandering) additionally when wandering behavior is documented — commonly paired with F02.81 but can be reported whenever wandering is a documented safety concern
✅	Sweep for all HCC-bearing comorbidities at every F02.80 encounter — Parkinson’s, CHF, DM with complications, malnutrition, CKD — all carry independent RAF weight under v28
✅	99483 is the highest-value CPT for dementia encounters — use it when all 9 elements are performed and documented; it reimburses significantly more than a standard E/M and is specifically designed for dementia assessment and care planning

---

📚 Sources

1. CMS/NCHS. ICD-10-CM Official Guidelines for Coding and Reporting, FY2026. Chapter 5 (Mental Disorders), Section I.C.5; Etiology/Manifestation Convention (Section I.B.13); Tabular List — F02.80, F02.8 subcategory, F02.A/B/C severity-specific expansions; Code First instructions under F02.

2. APA. Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, Text Revision (DSM-5-TR). Major Neurocognitive Disorder diagnostic criteria — corresponds to ICD-10-CM F02.x category.

3. CMS. 2026 Medicare Advantage CMS-HCC Model v28 — Final Risk Adjustment Coefficients and ICD-10-CM Mappings. HCC 125 (Severe Dementia), HCC 126 (Moderate Dementia), HCC 127 (Mild or Unspecified Dementia).

4. CMS. IPPS Final Rule FY2026 — MS-DRG Definitions Manual v43. MDC 01 (Nervous System) and MDC 19 (Mental Diseases) DRG logic.

5. Alzheimer’s Association. Billing Codes for Alzheimer’s and Related Dementia. CPT 99483 element requirements and ICD-10-CM code guidance. alz.org.

6. AMA. CPT Professional Edition 2026. Neurology subsection (95800-96020); Evaluation and Management; CPT 99483 guidelines.

7. CMS. MLN Matters — Cognitive Assessment and Care Plan Services, CPT Code 99483. ICN 909207.

8. CMS. NCCI Policy Manual for Medicare Services, current version. Chapter on psychiatry/neurology correct coding principles.