ICD-10 Code K55.33 – Stage 3 necrotizing enterocolitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K55.33 – Stage 3 necrotizing enterocolitis
What it is
K55.33 identifies advanced necrotizing enterocolitis, a serious intestinal disease in which bowel tissue becomes inflamed and begins to die. Use it when documentation specifically states stage 3 disease.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include abdominal distension, feeding intolerance, bloody stools, or imaging evidence of bowel injury, perforation, or severe necrosis.
When to use this code
Use K55.33 when the provider documents stage 3 necrotizing enterocolitis, or clearly describes advanced NEC with severe bowel damage. Confirm that the record supports the stage designation, especially in neonatal cases.
Do not use for
Do not use this code for suspected NEC, milder stages, or other causes of neonatal abdominal symptoms. Check documentation if the stage is not stated or if another intestinal disorder is documented.
Coding tip
If the stage is missing, query the provider rather than assuming K55.33.