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G91

G91: Hydrocephalus

Non-billable headerICD-10-CM

G91 is a non-billable header ICD-10-CM code for hydrocephalus. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1: never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

  • Arnold-Chiari syndrome with hydrocephalus (Q07.-)
  • congenital hydrocephalus (Q03.-)
  • spina bifida with hydrocephalus (Q05.-)

Includes

Conditions this code covers.

  • acquired hydrocephalus

Other codes that can never be billed with G91

Their own Excludes1 notes name this code, so the conflict is not listed above.

  • G93.2Benign intracranial hypertension
  • G94Other disorders of brain in diseases classified elsewhere
  • Q03Congenital hydrocephalus

Risk adjustment

No CMS-HCC V28 category: this code does not change a RAF score.

Code history

Unchanged in every release from FY2024 to FY2027.

Code to one of these instead G91

7 child codes. Green means billable.

ICD-10-CMFY2027· effective October 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release: see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.