ICD-10-CM 2027
ICD-10 code for hyperammonemia
Disorder of urea cycle metabolism, unspecified
From the official ICD-10-CM alphabetic index entry “Hyperammonemia (congenital)”. Page updated September 29, 2026.
About coding hyperammonemia
The ICD-10-CM code for hyperammonemia is E72.20 (Disorder of urea cycle metabolism, unspecified).
Within E72.2, choose E72.20 (Disorder of urea cycle metabolism, unspecified) only when documentation doesn't support a more specific option: Argininemia (E72.21), Arginosuccinic aciduria (E72.22), Citrullinemia (E72.23) and other disorders of urea cycle metabolism (E72.29).
Don't report E72.20 together with the conditions in its Excludes1 note: hyperammonemia-hyperornithinemia-homocitrullinemia syndrome E72.4 and transient hyperammonemia of newborn (P74.6).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
Don't confuse with (Excludes1 for E72.20)
Common questions about hyperammonemia ICD-10 codes
What is the ICD-10 code for hyperammonemia?
- E72.20 — Disorder of urea cycle metabolism, unspecified.
Is E72.20 billable?
- Yes. E72.20 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can E72.20 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict E72.20 as a principal diagnosis.
Is E72.20 a CC or MCC?
- E72.20 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.