G40 vs P90
G40 and P90 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on G40
seizure of newborn (P90)
P90
Convulsions of newborn
Billable
- Chapter 16
- Certain conditions originating in the perinatal period
- Section
- P90-P96
Indexed under
- Convulsions › infantile (idiopathic)
- Convulsions › newborn (idiopathic)
- Fit › newborn
- Newborn › convulsion (infant) (liveborn) (singleton)
- Newborn › seizure (infant) (liveborn) (singleton)
These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027