G31.09
BillableOther frontotemporal neurocognitive disorder
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G31.09 an HCC code?
Yes. G31.09 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 G31.09
For G31.09 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 G31.09 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G31.09 is the ICD-10-CM diagnosis code for other frontotemporal neurocognitive disorder. Other types of frontotemporal dementia that affect the front and temporal lobes of the brain, causing progressive cognitive and behavioral changes. G31.09 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, G31.09 maps to Dementia, Mild or Unspecified (HCC 127) with a community, non-dual, aged base RAF weight of 0.464. G31.09 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 for frontotemporal dementias other than Pick's disease; document the specific type when possible. Because G31.09 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 G31.09 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code for frontotemporal dementias other than Pick's disease; document the specific type when possible
- •This is a catch-all code for unspecified or other frontotemporal neurocognitive disorders
Clinical Significance
Other frontotemporal neurocognitive disorder captures frontotemporal dementias other than Pick's disease, including behavioral variant frontotemporal dementia, semantic dementia, and progressive nonfluent aphasia. These disorders cause progressive personality changes, language difficulties, and behavioral disturbances. They are important for risk adjustment as they require specialized neurology and behavioral health management.
Documentation Requirements
- ✓Documentation specifying frontotemporal dementia or frontotemporal neurocognitive disorder
- ✓Neuroimaging showing frontal and/or temporal lobe atrophy
- ✓Clinical assessment of behavioral, language, or executive function changes
- ✓Documentation that Pick's disease (G31.01) has been ruled out or is not specifically diagnosed
- ✓Neuropsychological testing results showing frontal/temporal pattern
- ✓Current treatment and management plan
Use Additional Code
- code, if applicable, to identify mild neurocognitive disorders due to known physiological condition (F06.7-)