A81.2
BillableProgressive multifocal leukoencephalopathy
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A81.2 an HCC code?
Yes. A81.2 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 A81.2
For A81.2 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 A81.2 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
A81.2 is the ICD-10-CM diagnosis code for progressive multifocal leukoencephalopathy. Progressive multifocal leukoencephalopathy (PML) is a rare and serious brain infection caused by a virus that damages the white matter of the brain, leading to progressive neurological decline. It typically occurs in people with weakened immune systems, such as those with HIV/AIDS or on certain immunosuppressive medications. A81.2 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, A81.2 maps to Dementia, Mild or Unspecified (HCC 127) with a community, non-dual, aged base RAF weight of 0.464. A81.2 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.
Always verify the patient has a confirmed diagnosis of PML, as this is a serious condition requiring specific diagnostic testing (MRI, CSF analysis, or brain biopsy); do not code based on clinical suspicion alone. Because A81.2 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 A81.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Always verify the patient has a confirmed diagnosis of PML, as this is a serious condition requiring specific diagnostic testing (MRI, CSF analysis, or brain biopsy); do not code based on clinical suspicion alone
- •When PML is present, investigate and code the underlying immunocompromised condition (such as B20 for HIV disease) as a secondary diagnosis, as PML is typically an opportunistic infection
Clinical Significance
Progressive multifocal leukoencephalopathy is a devastating demyelinating brain disease caused by JC virus reactivation in immunocompromised patients, particularly those with HIV/AIDS, hematologic malignancies, or on immunosuppressive therapy (notably natalizumab for multiple sclerosis). It carries high mortality and significant disability in survivors.
Documentation Requirements
- ✓Confirmed PML diagnosis via brain MRI showing characteristic white matter lesions (no contrast enhancement, no mass effect)
- ✓JC virus detection: CSF PCR for JC virus DNA or brain biopsy showing viral inclusions
- ✓Underlying immunocompromised condition documented (HIV with CD4 count, transplant status, immunosuppressive medications)
- ✓Neurological examination documenting focal deficits (hemiparesis, visual field cuts, cognitive impairment, ataxia)
- ✓Current antiretroviral therapy or immunosuppressive medication list