G30.0
BillableAlzheimer's disease with early onset
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G30.0 an HCC code?
Yes. G30.0 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 G30.0
For G30.0 to 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 G30.0 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G30.0 is the ICD-10-CM diagnosis code for alzheimer's disease with early onset. Alzheimer's disease that begins before age 65, causing progressive memory loss and cognitive decline in younger individuals. G30.0 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering other degenerative diseases of the nervous system (g30-g32).
Under the CMS-HCC V28 risk adjustment model, G30.0 maps to Dementia, Mild or Unspecified (HCC 127) with a community, non-dual, aged base RAF weight of 0.464. G30.0 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.
Document the age of onset and any behavioral or cognitive symptoms to support the early-onset designation. Because G30.0 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 G30.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the age of onset and any behavioral or cognitive symptoms to support the early-onset designation
- •Early-onset Alzheimer's may have different genetic factors; note any family history of dementia in the medical record
Clinical Significance
Alzheimer's disease with early onset (before age 65) represents a particularly impactful diagnosis due to its occurrence in younger patients who may still be in the workforce. Early-onset Alzheimer's often has stronger genetic components and may progress more rapidly than late-onset forms. It carries substantial care coordination needs including safety planning, caregiver support, and specialty neurology management.
Documentation Requirements
- ✓Documentation that symptoms began before age 65
- ✓Cognitive assessment results (e.g., MMSE, MoCA scores) demonstrating progressive decline
- ✓Neuroimaging findings consistent with Alzheimer's disease (cortical atrophy, hippocampal volume loss)
- ✓Documentation of functional status and activities of daily living impact
- ✓Current medication management (cholinesterase inhibitors, memantine) and care plan
- ✓Family history of early-onset dementia if applicable
Commonly Confused Codes
- •G30.1 — Alzheimer's disease with late onset; use when onset is at age 65 or older
- •G30.9 — Alzheimer's disease, unspecified; use only when age of onset is not documented
- •G31.83 — Neurocognitive disorder with Lewy bodies; different dementia type with visual hallucinations and parkinsonism
- •G31.09 — Other frontotemporal neurocognitive disorder; presents with personality/behavioral changes rather than memory loss
- •F02.80 — Dementia in other diseases classified elsewhere, without behavioral disturbance; used as a manifestation code with G30.0 sequenced first