G31

ICD-10Non-billable category

Oth degenerative diseases of nervous system, NEC

Official ICD-10-CM descriptor (FY2026)

Other degenerative diseases of nervous system, not elsewhere classified

G31 is a category heading, not a billable code. CMS does not accept it on a claim; report one of the more specific codes beneath it.

Excludes2

Not included here. The condition is not part of this code, but a patient may have both, and both codes may be reported together.

  • Reye's syndrome (G93.7)

Use additional code

Report an additional code to identify the associated condition.

  • code, if applicable, for codes G31.0-G31.83, G31.85-G31.9, to identify:
  • dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4)
  • dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-)
  • dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3)
  • dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2)
  • dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0)
  • mild neurocognitive disorder due to known physiological condition (F06.7-)

More specific codes under G31

Where this code sits

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Source

ICD-10-CM FY2026. Centers for Medicare & Medicaid Services (CMS) / National Center for Health Statistics (NCHS), “2026 ICD-10-CM Code Descriptions in Tabular Order” (icd10cm_order_2026.txt). Download the original file from cms.gov. Public domain (US Government work). Descriptors, billable flags and instructional notes on this page are reproduced from that file without modification. Krasyn adds no clinical guidance.

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