G35.D ICD-10-CM Code: Multiple sclerosis, unspecified

G35.D is the ICD-10-CM diagnosis code for multiple sclerosis, unspecified. Multiple sclerosis when the specific type or pattern of the disease has not been clearly identified or documented. G35.D 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, G35.D maps to Multiple Sclerosis (HCC 198) with a community, non-dual, aged base RAF weight of 0.000. G35.D 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.

Use this code only when the clinical documentation does not specify the MS type (relapsing-remitting, progressive, etc.). Because G35.D 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.