G40.81 vs P90
G40.81 (Lennox-Gastaut syndrome) compared with P90 (Convulsions of newborn), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. G40.81 carries an Excludes1 note covering P90: “seizure of newborn (P90)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| G40.81Lennox-Gastaut syndrome | P90Convulsions of newborn | |
|---|---|---|
| Billing status | Non-billable header | Billable |
| Classification | G00-G99 — Diseases of the Nervous System (G00-G99) | P00-P96 — Certain Conditions Originating in the Perinatal Period (P00-P96) |
| Definition | Lennox-Gastaut syndrome is a non-billable ICD-10-CM category code (G40.81). | Convulsions of newborn is a billable ICD-10-CM diagnosis code (P90). |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources