G36.0
BillableNeuromyelitis optica [Devic]
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G36.0 an HCC code?
Yes. G36.0 maps to Multiple Sclerosis under the CMS-HCC V28 risk adjustment model (and Multiple Sclerosis under V24).
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 G36.0
For G36.0 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 G36.0 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G36.0 is the ICD-10-CM diagnosis code for neuromyelitis optica [devic]. A rare autoimmune disease affecting the optic nerves and spinal cord, causing inflammation and demyelination that leads to vision loss and paralysis. G36.0 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering demyelinating diseases of the central nervous system (g35-g37).
Under the CMS-HCC V28 risk adjustment model, G36.0 maps to Multiple Sclerosis (HCC 198) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, G36.0 mapped to the same category but with a base RAF weight of 0.476 — V28 recalibrated weights across the entire model. 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.
Confirm diagnosis is specifically neuromyelitis optica (NMO) and not multiple sclerosis, as they are distinct conditions. Because G36.0 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 G36.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm diagnosis is specifically neuromyelitis optica (NMO) and not multiple sclerosis, as they are distinct conditions
- •Document involvement of optic nerves and spinal cord to support medical necessity
Clinical Significance
Neuromyelitis optica (Devic's disease) is a rare autoimmune demyelinating disorder affecting the optic nerves and spinal cord. It is now recognized as a distinct entity from multiple sclerosis, with different pathophysiology (aquaporin-4 antibodies), treatment approaches, and prognosis. Accurate identification is critical because standard multiple sclerosis treatments may worsen neuromyelitis optica.
Documentation Requirements
- ✓Provider documentation specifically stating neuromyelitis optica or Devic's disease
- ✓Aquaporin-4 (AQP4) antibody testing results (positive supports diagnosis)
- ✓Documentation of optic neuritis and/or transverse myelitis episodes
- ✓MRI findings showing longitudinally extensive transverse myelitis (3+ vertebral segments) and/or optic nerve inflammation
- ✓Current immunosuppressive treatment plan (eculizumab, inebilizumab, satralizumab)
- ✓Documentation of disease course including attack frequency and disability level
Excludes 1 — Do NOT code together
- optic neuritis NOS (H46)