2026 ICD-10-CM Diagnosis Code P91.811Neonatal encephalopathy in diseases classified elsewhere

ICD-10-CM Codes›P00–P96›P90-P96›P91

ICD-10-CM P91.811
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

P91.811 is a billable ICD-10-CM diagnosis code for neonatal encephalopathy in diseases classified elsewhere. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is a manifestation code that cannot be reported as the principal diagnosis and exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Neonatal cerebral disorders.

Code Identity

ICD-10-CM Code
P91.811
Billable Status
Yes — Valid for Submission
Code Describes
Neonatal encephalopathy in diseases classified elsewhere
Short Description
Neonatal encephalopathy in diseases classified elsewhere
Same as the full description in the CMS dataset.
Parent Code
P91.81
Neonatal encephalopathy

Code Classification

ChapterP00–P96Certain conditions originating in the perinatal period
SectionP90-P96Other disorders originating in the perinatal period
CategoryP91Other disturbances of cerebral status of newborn
This CodeP91.811Neonatal encephalopathy in diseases classified elsewhere

Code EditsBilling

Medicare Code Editor checks that affect claim validity for P91.811.

Manifestation diagnoses
Manifestation codes describe the manifestation of an underlying disease, not the disease itself, and therefore should not be used as a principal diagnosis.

Present on Admission (POA)Billing

P91.811 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Autoimmune thyroiditis
  • Cortical blindness
  • Disorder of glutamine metabolism
  • Early infantile developmental and epileptic encephalopathy
  • Early-onset epileptic encephalopathy, cortical blindness, intellectual disability, facial dysmorphism syndrome
  • Hyperglycinemia
  • Infantile epileptic dyskinetic encephalopathy
  • Infantile glycine encephalopathy
  • KCNQ2 developmental and epileptic encephalopathy
  • Neonatal epileptic encephalopathy due to glutaminase deficiency
  • Neonatal glycine encephalopathy
  • Neonatal metabolic acidemia
  • Non-ketotic hyperglycinemia
  • Steroid-responsive encephalopathy associated with autoimmune thyroiditis

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Code First

  • underlying condition, if known, such as:
  • congenital cirrhosis of liver P78.81
  • intracranial nontraumatic hemorrhage of newborn P52
  • kernicterus P57

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Encephalopathy(acute)
      • neonatal
        • in diseases classified elsewhere

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR PNL004
Neonatal cerebral disorders
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • Cortical Blindness

    visual impairment due to visual cortex dysfunction.

Convert P91.811 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
779.1 NB cereb irrit NEC/NOS
Approximate The match is approximate rather than exact.

Code History & ChangesHistory

Replacement P91.811 replaces the following previously assigned code(s):

  • P91.8 - Other specified disturbances of cerebral status of newborn
FY 2018AddedAdded to the ICD-10-CM code setEffective October 1, 2017.
FY 2019–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About P91.811Overview

Is P91.811 (Neonatal encephalopathy) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report neonatal encephalopathy in diseases classified elsewhere on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Can P91.811 be a principal diagnosis?

No. This is a manifestation code: neonatal encephalopathy in diseases classified elsewhere describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.

Is P91.811 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for neonatal encephalopathy in diseases classified elsewhere on inpatient claims.

What is the ICD-9 equivalent of P91.811?

Under the General Equivalence Mappings, neonatal encephalopathy in diseases classified elsewhere converts to ICD-9-CM 779.1 (NB cereb irrit NEC/NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.