F01.A18
BillableVascular dementia, mild, with other behavioral disturbance
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is F01.A18 an HCC code?
Yes. F01.A18 maps to Dementia, Mild or Unspecified under the CMS-HCC V28 risk adjustment model.
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for F01.A18
For F01.A18to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed F01.A18 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
F01.A18 is the ICD-10-CM diagnosis code for vascular dementia, mild, with other behavioral disturbance. Early-stage dementia caused by reduced blood flow to the brain with behavioral problems other than agitation. F01.A18 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering mental disorders due to known physiological conditions (f01-f09).
Under the CMS-HCC V28 risk adjustment model, F01.A18 maps to Dementia, Mild or Unspecified (HCC 127) with a community, non-dual, aged base RAF weight of 0.464. F01.A18 was not retained as a payment HCC under the older V24 model, so V28 introduced or recategorized it during the 2024–2026 phase-in. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
This code captures behavioral disturbances like wandering, inappropriate behavior, or personality changes in mild vascular dementia. Because F01.A18 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for F01.A18 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code captures behavioral disturbances like wandering, inappropriate behavior, or personality changes in mild vascular dementia
- •Ensure documentation specifies the type of behavioral disturbance to support medical necessity
Clinical Significance
Mild vascular dementia with other behavioral disturbance captures early-stage vascular cognitive decline with non-agitation behavioral symptoms such as wandering, sundowning, inappropriate social behavior, or sleep-wake cycle disturbances. These symptoms often herald progression and require environmental and behavioral interventions.
Documentation Requirements
- ✓Diagnosis of vascular dementia with cerebrovascular etiology
- ✓Severity explicitly documented as 'mild'
- ✓Specific behavioral disturbance described (not agitation — use F01.A11 for agitation)
- ✓Cognitive assessment supporting mild stage
- ✓Impact of behavioral disturbance on daily function and safety
- ✓Management plan for the specific behavioral issue
Use Additional Code
- code, if applicable, to identify wandering in vascular dementia (Z91.83)
Commonly Confused Codes
- •F01.A11 — Vascular dementia, mild, with agitation: use specifically when agitation is the behavioral issue
- •F01.A0 — Vascular dementia, mild, without behavioral disturbance: use when no behavioral issues are present
- •F01.A2 — Vascular dementia, mild, with psychotic disturbance: for hallucinations or delusions
- •F01.518 — Vascular dementia, unspecified severity, with other behavioral disturbance: less specific for severity