P77.3
BillableStage 3 necrotizing enterocolitis in newborn
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is P77.3 an HCC code?
Yes. P77.3 maps to Intestinal Obstruction/Perforation under the CMS-HCC V28 risk adjustment model.
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for P77.3
For P77.3 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed P77.3 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
P77.3 is the ICD-10-CM diagnosis code for stage 3 necrotizing enterocolitis in newborn. Severe stage necrotizing enterocolitis in a newborn with intestinal perforation and peritonitis, representing the most critical form of the disease. P77.3 sits in the ICD-10-CM chapter for certain conditions originating in the perinatal period (p00-p96), within the section covering digestive system disorders of newborn (p76-p78).
Under the CMS-HCC V28 risk adjustment model, P77.3 maps to Intestinal Obstruction/Perforation (HCC 78) with a community, non-dual, aged base RAF weight of 0.000. P77.3 was not retained as a payment HCC under the older V24 model, so V28 introduced or recategorized it during the 2024–2026 phase-in. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Stage 3 NEC indicates perforation; document evidence of free air, peritonitis, or surgical findings confirming perforation. Because P77.3 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for P77.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Stage 3 NEC indicates perforation; document evidence of free air, peritonitis, or surgical findings confirming perforation
- •This is a critical condition requiring immediate intervention; ensure all complications are coded separately (e.g., peritonitis, sepsis)
Clinical Significance
Stage 3 NEC represents the most severe form requiring immediate surgical intervention due to intestinal perforation and peritonitis. This life-threatening condition has high morbidity and mortality rates, requiring intensive multidisciplinary care and long-term monitoring for complications.
Documentation Requirements
- ✓Radiographic evidence of pneumoperitoneum or intestinal perforation
- ✓Clinical signs of peritonitis and systemic deterioration
- ✓Surgical consultation and intervention documentation
- ✓Evidence of hemodynamic instability or shock
- ✓Laboratory findings consistent with severe illness
- ✓Operative reports if surgery performed
- ✓Intensive care management documentation
- ✓Long-term outcome and complication monitoring
Commonly Confused Codes
- •P77.1 — Stage 1 necrotizing enterocolitis (early stage without perforation)
- •P77.2 — Stage 2 necrotizing enterocolitis (pneumatosis without perforation)
- •P77.9 — Necrotizing enterocolitis, unspecified (stage not documented)
- •P78.1 — Other perinatal intestinal perforation (perforation from other causes)