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A81.09 ICD-10-CM Code: Other Creutzfeldt-Jakob disease

A81.09 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 · HCC Buddy coding tools

ICD-10-CM Code View

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Code lookupA81.09

FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Viral and prion infections of the central nervous system (A80-A89)

A81.09

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

Other Creutzfeldt-Jakob disease

This is a rare, rapidly progressive brain disease that causes severe dementia and loss of brain function, similar to Creutzfeldt-Jakob disease but not fitting the typical presentation. It is caused by abnormal proteins called prions and is always fatal.

Buddy the Bee presenting code insight

Buddy Insight

This code captures CJD subtypes not classified as unspecified or variant, including sporadic CJD (the most common form, ~85% of cases), familial CJD, and iatrogenic CJD from contaminated surgical instruments or transplants.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 127

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

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

N/A

—

Not mapped

ESRD/PACE

HCC 52

Code-level coefficient reference

RXHCC

HCC 112

Code-level coefficient reference

Code Book Path

Official
A81Atypical virus infections of central nervous systemA81.0Creutzfeldt-Jakob diseaseA81.09Other Creutzfeldt-Jakob disease

Inclusion Terms

Official
  • CJD
  • Familial Creutzfeldt-Jakob disease
  • Iatrogenic Creutzfeldt-Jakob disease
  • Sporadic Creutzfeldt-Jakob disease
  • Subacute spongiform encephalopathy (with dementia)

Excludes 2

Official
  • carrier or suspected carrier of infectious disease (Z22.-)Inherited from A00-B99
  • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)Inherited from A00-B99
  • infectious and parasitic diseases specific to the perinatal period (P35-P39)Inherited from A00-B99
  • influenza and other acute respiratory infections (J00-J22)Inherited from A00-B99

Related Codes

Official
A81.00Creutzfeldt-Jakob disease, unspecifiedA81.01Variant Creutzfeldt-Jakob disease

Includes

Official
  • diseases generally recognized as communicable or transmissibleInherited from A00-B99, A81
  • diseases of the central nervous system caused by prionsInherited from A00-B99, A81

Excludes 1

Official
  • certain localized infections - see body system-related chaptersInherited from A00-B99, A80-A89
  • postpolio syndrome (G14)Inherited from A00-B99, A80-A89
  • sequelae of poliomyelitis (B91)Inherited from A00-B99, A80-A89
  • sequelae of viral encephalitis (B94.1)Inherited from A00-B99, A80-A89

Code First

Official

No Code First sequencing instructions are included in this display for A81.09. Check the code and parent instructions in the Code Book.

Use Additional

Official
  • code to identify resistance to antimicrobial drugs (Z16.-)Inherited from A00-B99, A81
  • code, if applicable, to identify:Inherited from A00-B99, A81
  • dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4)Inherited from A00-B99, A81
  • dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-)Inherited from A00-B99, A81
  • dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3)Inherited from A00-B99, A81
  • dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2)Inherited from A00-B99, A81
  • dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0)Inherited from A00-B99, A81
  • mild neurocognitive disorder due to known physiological condition (F06.7-)Inherited from A00-B99, A81

Code Also

Official

No Code Also instructions are included in this display for A81.09. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
Specific CJD subtype documented (sporadic, familial, iatrogenic)
Genetic testing results for familial CJD (PRNP gene mutation)
For iatrogenic CJD: source of exposure (dura mater graft, corneal transplant, growth hormone, contaminated instruments)
Diagnostic criteria and confirmatory testing results

MEAT Support

HCC Buddy guidance
Specific CJD subtype documented (sporadic, familial, iatrogenic)
Genetic testing results for familial CJD (PRNP gene mutation)
For iatrogenic CJD: source of exposure (dura mater graft, corneal transplant, growth hormone, contaminated instruments)
Diagnostic criteria and confirmatory testing results

Audit Caution

HCC Buddy guidance
Using A81.00 (unspecified) when the provider has documented the specific CJD subtype — always code to highest specificity
Confusing familial CJD (A81.09) with Gerstmann-Straussler-Scheinker syndrome (A81.82), which is a separate hereditary prion disease
Not documenting the mode of transmission for iatrogenic cases, which has medicolegal implications
Failing to capture the genetic component in familial cases with appropriate additional codes

Common Mistakes

HCC Buddy guidance
A81.00 (Creutzfeldt-Jakob disease, unspecified) — Use A81.00 only when the subtype cannot be determined; A81.09 indicates a known subtype that is not the variant form
A81.01 (Variant Creutzfeldt-Jakob disease) — vCJD is BSE-related; A81.09 covers other specific subtypes
A81.82 (Gerstmann-Straussler-Scheinker syndrome) — Another familial prion disease but with distinct clinical features (cerebellar ataxia predominates over dementia)

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 A81.09 an HCC code?

Yes. A81.09 (Other Creutzfeldt-Jakob 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: A81.09 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
A81.09
Description
Other Creutzfeldt-Jakob 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 112, Dementia, Except 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 A81.09 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for A81.09

For A81.09, 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

A81.09 is the ICD-10-CM diagnosis code for other creutzfeldt-jakob disease. This is a rare, rapidly progressive brain disease that causes severe dementia and loss of brain function, similar to Creutzfeldt-Jakob disease but not fitting the typical presentation. It is caused by abnormal proteins called prions and is always fatal. A81.09 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering viral and prion infections of the central nervous system (a80-a89).

Under the CMS-HCC V28 risk adjustment model, A81.09 maps to Dementia, Mild or Unspecified (HCC 127) with a source-labeled community, non-dual, aged reference coefficient of 0.341. No V24 mapping is shown for A81.09; use the applicable model and payment year when reviewing the V28 mapping. 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.

Verify the specific type of CJD documented in the medical record, as code A81.09 is used only when the CJD variant doesn't fit other specified categories (A81.00, A81.01, A81.02). For A81.09, 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 A81.09 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Verify the specific type of CJD documented in the medical record, as code A81.09 is used only when the CJD variant doesn't fit other specified categories (A81.00, A81.01, A81.02)
  • •This is a reportable disease in most jurisdictions; ensure proper documentation and reporting requirements are met per local health department guidelines

Clinical Significance

This code captures CJD subtypes not classified as unspecified or variant, including sporadic CJD (the most common form, ~85% of cases), familial CJD, and iatrogenic CJD from contaminated surgical instruments or transplants. Proper subtype identification is critical for epidemiological surveillance and family counseling.

Documentation Requirements

  • ✓Specific CJD subtype documented (sporadic, familial, iatrogenic)
  • ✓Genetic testing results for familial CJD (PRNP gene mutation)
  • ✓For iatrogenic CJD: source of exposure (dura mater graft, corneal transplant, growth hormone, contaminated instruments)
  • ✓Diagnostic criteria and confirmatory testing results
  • ✓Family history of prion disease if familial subtype is suspected

Commonly Confused Codes

  • •A81.00 (Creutzfeldt-Jakob disease, unspecified): Use A81.00 only when the subtype cannot be determined; A81.09 indicates a known subtype that is not the variant form
  • •A81.01 (Variant Creutzfeldt-Jakob disease): vCJD is BSE-related; A81.09 covers other specific subtypes
  • •A81.82 (Gerstmann-Straussler-Scheinker syndrome): Another familial prion disease but with distinct clinical features (cerebellar ataxia predominates over dementia)

Child Codes

A81.00Creutzfeldt-Jakob disease, unspecified
HCC 127
A81.01Variant Creutzfeldt-Jakob disease
HCC 127
A81.09Other Creutzfeldt-Jakob disease
HCC 127

Code Hierarchy

└A81Atypical virus infections of central nervous system└A81.0Creutzfeldt-Jakob disease└A81.09Other Creutzfeldt-Jakob disease
└A81.09Other Creutzfeldt-Jakob disease

Also searched as

  • A81 09
  • A8109

For A81.09, 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.

A81.09 maps to CMS-HCC V28 category 127, Dementia, Mild or Unspecified. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for A81.09. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

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Open A81.09 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

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