G30.9
BillableAlzheimer's disease, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G30.9 an HCC code?
Yes. G30.9 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 G30.9
For G30.9 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 G30.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G30.9 is the ICD-10-CM diagnosis code for alzheimer's disease, unspecified. Alzheimer's disease without specification of the stage or type; the most common form of dementia causing progressive memory loss and cognitive decline. G30.9 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, G30.9 maps to Dementia, Mild or Unspecified (HCC 127) with a community, non-dual, aged base RAF weight of 0.464. G30.9 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.
Use this code only when the specific stage (early, intermediate, late) or type of Alzheimer's is not documented; query the provider for more specificity if available. Because G30.9 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 G30.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when the specific stage (early, intermediate, late) or type of Alzheimer's is not documented; query the provider for more specificity if available
- •This code should not be used if behavioral disturbances or delirium are documented, as those require additional codes
Clinical Significance
Alzheimer's disease, unspecified, captures confirmed Alzheimer's diagnoses where the onset type or variant has not been documented. While it carries the same HCC value as more specific Alzheimer's codes, it represents a documentation improvement opportunity. Accurate capture still ensures proper risk adjustment for these patients with progressive cognitive decline requiring substantial care resources.
Documentation Requirements
- ✓Provider documentation confirming Alzheimer's disease diagnosis
- ✓Cognitive assessment demonstrating decline (MMSE, MoCA, or equivalent)
- ✓Evidence of progressive memory loss and functional impairment
- ✓Current medication management and care plan
- ✓Assessment for associated behavioral or psychological symptoms
Commonly Confused Codes
- •G30.0 — Alzheimer's disease with early onset; query provider if onset age is available
- •G30.1 — Alzheimer's disease with late onset; query provider if onset age is documented
- •F03.90 — Unspecified dementia; too vague if Alzheimer's has been specifically diagnosed
- •G31.84 — Mild cognitive impairment; a milder condition that may precede Alzheimer's but is not the same
- •R41.81 — Age-related cognitive decline; normal aging, not Alzheimer's disease