Necrotizing enterocolitis of newborn (P77) ICD-10-CM
The P77 code range covers necrotizing enterocolitis of newborn with 5 ICD-10-CM diagnosis codes. 4 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Codes in the P77 Range 5 codes · 4 billable
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the P77 range.
Colitis
Inflammation of the COLON section of the large intestine (INTESTINE, LARGE), usually with symptoms such as DIARRHEA (often with blood and mucus), ABDOMINAL PAIN, and FEVER.
Colitis, Collagenous
A subtype of MICROSCOPIC COLITIS, characterized by chronic watery DIARRHEA of unknown origin, a normal COLONOSCOPY but abnormal histopathology on BIOPSY. Microscopic examination of biopsy samples taken from the COLON show larger-than-normal band of subepithelial COLLAGEN.
Colitis, Ischemic
Inflammation of the COLON due to colonic ISCHEMIA resulting from alterations in systemic circulation or local vasculature.
Colitis, Lymphocytic
A subtype of MICROSCOPIC COLITIS, characterized by chronic watery DIARRHEA of unknown origin, a normal COLONOSCOPY but abnormal histopathology on BIOPSY. Microscopic examination of biopsy samples taken from the COLON show infiltration of LYMPHOCYTES in the superficial EPITHELIUM and the underlying connective tissue (lamina propria).
Colitis, Microscopic
A condition characterized by chronic watery DIARRHEA of unknown origin, a normal COLONOSCOPY but abnormal histopathology on BIOPSY. This syndrome was first described in 1980 by Read and associates. Subtypes include COLLAGENOUS COLITIS and LYMPHOCYTIC COLITIS. Both have similar clinical symptoms and are distinguishable only by histology.
Colitis, Ulcerative
Inflammation of the COLON that is predominantly confined to the MUCOSA. Its major symptoms include DIARRHEA, rectal BLEEDING, the passage of MUCUS, and ABDOMINAL PAIN.
Colitis-Associated Neoplasms
Colonic neoplasms associated with chronic inflammation conditions such as ULCERATIVE COLITIS and CROHN DISEASE.
Coronavirus
A member of CORONAVIRIDAE which causes respiratory or gastrointestinal disease in a variety of vertebrates.
Crohn Disease
A chronic transmural inflammation that may involve any part of the DIGESTIVE TRACT from MOUTH to ANUS, mostly found in the ILEUM, the CECUM, and the COLON. In Crohn disease, the inflammation, extending through the intestinal wall from the MUCOSA to the serosa, is characteristically asymmetric and segmental. Epithelioid GRANULOMAS may be seen in some patients.
Cytomegalovirus
A genus of the family HERPESVIRIDAE, subfamily BETAHERPESVIRINAE, infecting the salivary glands, liver, spleen, lungs, eyes, and other organs, in which they produce characteristically enlarged cells with intranuclear inclusions. Infection with Cytomegalovirus is also seen as an opportunistic infection in AIDS.
Cytomegalovirus Infections
Infection with CYTOMEGALOVIRUS, characterized by enlarged cells bearing intranuclear inclusions. Infection may be in almost any organ, but the salivary glands are the most common site in children, as are the lungs in adults.
Dysentery, Amebic
DYSENTERY caused by intestinal amebic infection, chiefly with ENTAMOEBA HISTOLYTICA. This condition may be associated with amebic infection of the LIVER and other distant sites.
Enterocolitis, Pseudomembranous
An acute inflammation of the INTESTINAL MUCOSA that is characterized by the presence of pseudomembranes or plaques in the SMALL INTESTINE (pseudomembranous enteritis) and the LARGE INTESTINE (pseudomembranous colitis). It is commonly associated with antibiotic therapy and CLOSTRIDIUM DIFFICILE colonization.
Gastroenteritis
INFLAMMATION of any segment of the GASTROINTESTINAL TRACT from ESOPHAGUS to RECTUM. Causes of gastroenteritis are many including genetic, infection, HYPERSENSITIVITY, drug effects, and CANCER.
Gastroenteritis, Transmissible, of Swine
A condition of chronic gastroenteritis in adult pigs and fatal gastroenteritis in piglets caused by a CORONAVIRUS.
Irritable Bowel Syndrome
A disorder with chronic or recurrent colonic symptoms without a clearcut etiology. This condition is characterized by chronic or recurrent ABDOMINAL PAIN, bloating, MUCUS in FECES, and an erratic disturbance of DEFECATION.
Murine hepatitis virus
A species of the CORONAVIRUS genus causing hepatitis in mice. Four strains have been identified as MHV 1, MHV 2, MHV 3, and MHV 4 (also known as MHV-JHM, which is neurotropic and causes disseminated encephalomyelitis with demyelination as well as focal liver necrosis).
Transmissible gastroenteritis virus
A species of CORONAVIRUS causing a fatal disease to pigs under 3 weeks old.
About the P77 Code Range
ICD-10 code P77 is used to identify necrotizing enterocolitis (NEC) in newborns, a serious intestinal condition that affects infants, especially premature babies. This code includes different stages of NEC severity to specify the progression of the disease.
The subcodes P77.1, P77.2, and P77.3 correspond to stages 1, 2, and 3 of neonatal necrotizing enterocolitis, respectively. These stages describe increasing severity, from early inflammation and mild symptoms (stage 1) to more advanced damage and complications (stage 3). Terms like “neonatal necrotizing enterocolitis,” or stage-specific names such as “necrotizing enterocolitis of newborn, stage 1A or 1B,” help medical coders link clinical descriptions back to the right ICD-10 code. The P77.9 code is used when the NEC diagnosis is confirmed but the specific stage is not documented, covering general conditions labeled as neonatal necrotizing enterocolitis or related terms like “perinatal necrotizing enterocolitis.” Understanding the stages and synonyms improves accurate coding for these neonatal digestive and feeding disorders.
Questions About This Page
How many billable codes are in the P77 range?
Of the 5 codes in this range, 4 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the P77 range classify?
The range classifies necrotizing enterocolitis of newborn. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
