A81.09
BillableOther Creutzfeldt-Jakob disease
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A81.09 an HCC code?
Yes. A81.09 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 A81.09
For A81.09 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 A81.09 during that encounter — not just copy-forwarded from a problem list.
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 community, non-dual, aged base RAF weight of 0.464. A81.09 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.
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). Because A81.09 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 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)