K55.031 vs P77
K55.031 (Focal (segmental) acute (reversible) ischemia of large intestine) compared with P77 (Necrotizing enterocolitis 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. K55.031 carries an Excludes1 note covering P77: “necrotizing enterocolitis of newborn (P77.-)”
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
| K55.031Focal (segmental) acute (reversible) ischemia of large intestine | P77Necrotizing enterocolitis of newborn | |
|---|---|---|
| Billing status | Billable | Non-billable header |
| Classification | K00-K95 — Diseases of the Digestive System (K00-K95) | P00-P96 — Certain Conditions Originating in the Perinatal Period (P00-P96) |
| Definition | Focal (segmental) acute (reversible) ischemia of large intestine is a billable ICD-10-CM diagnosis code (K55.031). | Necrotizing enterocolitis of newborn is a non-billable ICD-10-CM category code (P77). |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources