G30.8 maps to CMS-HCC V28 127. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupG30.8

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Other degenerative diseases of the nervous system (G30-G32)

G30.8

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Other Alzheimer's disease

Other forms or presentations of Alzheimer's disease that don't fit the typical early or late-onset categories.

Buddy Insight

Other Alzheimer's disease captures atypical presentations that do not fit standard early-onset or late-onset classification, such as posterior cortical atrophy variant or logopenic variant.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 127

Dementia, Mild or Unspecified

Coefficient HCC 127: 0.341 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ESRD/PACE

Mapped

HCC 52

Dementia Without Complication

Code-level coefficient reference

RXHCC

Mapped

HCC 111

Alzheimer's Disease

Code-level coefficient reference

Code Book Path

Official

G30Alzheimer's disease G30.8Other Alzheimer's disease

Inclusion Terms

Official

No inclusion terms are included in this display for G30.8. Check the code and parent instructions in the Code Book.

Excludes 2

Official

certain conditions originating in the perinatal period (P04-P96)Inherited from G00-G99
certain infectious and parasitic diseases (A00-B99)Inherited from G00-G99
complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from G00-G99
congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from G00-G99
endocrine, nutritional and metabolic diseases (E00-E88)Inherited from G00-G99
injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from G00-G99
neoplasms (C00-D49)Inherited from G00-G99
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from G00-G99

Related Codes

Official

G30.0Alzheimer's disease with early onset G30.1Alzheimer's disease with late onset G30.9Alzheimer's disease, unspecified

Includes

Official

Alzheimer's dementia senile and presenile formsInherited from G30

Excludes 1

Official

senile degeneration of brain NEC (G31.1)Inherited from G30
senile dementia NOS (F03.-)Inherited from G30
senility NOS (R41.81)Inherited from G30

Code First

Official

No Code First sequencing instructions are included in this display for G30.8. Check the code and parent instructions in the Code Book.

Use Additional

Official

code, if applicable, to identify:Inherited from G30
delirium, if applicable (F05)Inherited from G30
dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4)Inherited from G30
dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-)Inherited from G30
dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3)Inherited from G30
dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2)Inherited from G30
dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0)Inherited from G30
mild neurocognitive disorder due to known physiological condition (F06.7-)Inherited from G30

Code Also

Official

No Code Also instructions are included in this display for G30.8. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Documentation specifying the atypical variant or presentation of Alzheimer's disease

Cognitive and neuropsychological testing results

Neuroimaging supporting Alzheimer's pathology pattern

Clinical rationale for why the case does not fit early-onset (G30.0) or late-onset (G30.1) categories

MEAT Support

HCC Buddy guidance

Documentation specifying the atypical variant or presentation of Alzheimer's disease

Cognitive and neuropsychological testing results

Neuroimaging supporting Alzheimer's pathology pattern

Clinical rationale for why the case does not fit early-onset (G30.0) or late-onset (G30.1) categories

Audit Caution

HCC Buddy guidance

Using G30.8 when the age of onset is documented and G30.0 or G30.1 would be more appropriate

Confusing atypical Alzheimer's variants with non-Alzheimer's dementias that have their own specific codes

Failing to add the required dementia manifestation code (F02.8x) as an additional diagnosis

Not documenting the specific reason the case qualifies as 'other' Alzheimer's disease

Common Mistakes

HCC Buddy guidance

G30.0 — Alzheimer's disease with early onset; use when onset before age 65 is confirmed

G30.1 — Alzheimer's disease with late onset; use when onset at age 65+ is confirmed

G30.9 — Alzheimer's disease, unspecified; use when no information about onset or variant is available

G31.09 — Other frontotemporal neurocognitive disorder; different dementia subtype affecting frontal/temporal lobes

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is G30.8 an HCC code?

Yes. G30.8 (Other Alzheimer's disease) maps to HCC 127, Dementia, Mild or Unspecified under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.341. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: G30.8 is billable and maps to V28 HCC 127, Dementia, Mild or Unspecified. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: G30.8
Description: Other Alzheimer's disease
HCC (V28): HCC 127 — Dementia, Mild or Unspecified
RAF reference coefficient: 0.341
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 127, Dementia, Mild or Unspecified

0.341

ESRDHCC 52, Dementia Without Complication

Not separately weighted

RxHCCHCC 111, Alzheimer's Disease

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work G30.8 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for G30.8

For G30.8, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

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

Coder workflow notes

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What This Code Means

G30.8 is the ICD-10-CM diagnosis code for other alzheimer's disease. Other forms or presentations of Alzheimer's disease that don't fit the typical early or late-onset categories. G30.8 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, G30.8 maps to Dementia, Mild or Unspecified (HCC 127) with a source-labeled community, non-dual, aged reference coefficient of 0.341. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Use this code for atypical presentations of Alzheimer's disease; clearly document the specific variant or presentation. For G30.8, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for G30.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use this code for atypical presentations of Alzheimer's disease; clearly document the specific variant or presentation
•Ensure that the diagnosis of Alzheimer's disease has been confirmed through appropriate clinical and diagnostic evaluation

Clinical Significance

Other Alzheimer's disease captures atypical presentations that do not fit standard early-onset or late-onset classification, such as posterior cortical atrophy variant or logopenic variant. These patients often present diagnostic challenges and may require more extensive workup. Accurate coding ensures proper resource allocation for these complex neurodegenerative cases.

Documentation Requirements

✓Documentation specifying the atypical variant or presentation of Alzheimer's disease
✓Cognitive and neuropsychological testing results
✓Neuroimaging supporting Alzheimer's pathology pattern
✓Clinical rationale for why the case does not fit early-onset (G30.0) or late-onset (G30.1) categories
✓Current treatment plan and specialist involvement

Commonly Confused Codes

•G30.0: Alzheimer's disease with early onset; use when onset before age 65 is confirmed
•G30.1: Alzheimer's disease with late onset; use when onset at age 65+ is confirmed
•G30.9: Alzheimer's disease, unspecified; use when no information about onset or variant is available
•G31.09: Other frontotemporal neurocognitive disorder; different dementia subtype affecting frontal/temporal lobes
•G31.83: Neurocognitive disorder with Lewy bodies; distinct pathology with Lewy body inclusions