2026 ICD-10-CM Diagnosis Code J10.81Influenza due to other identified influenza virus with encephalopathy

ICD-10-CM Codes›J00–J99›J09-J18›J10

ICD-10-CM J10.81
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

J10.81 is a billable ICD-10-CM diagnosis code for influenza due to other identified influenza virus with encephalopathy. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 865 through 866. Coders also document this condition as encephalopathy caused by Influenza A virus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Influenza and Other nervous system disorders (neither hereditary nor degenerative).

Code Identity

ICD-10-CM Code
J10.81
Billable Status
Yes — Valid for Submission
Code Describes
Influenza due to other identified influenza virus with encephalopathy
Short Description
Influenza due to oth ident influenza virus w encephalopathy
Parent Code
J10.8
Influenza due to other identified influenza virus with other manifestations

Code Classification

ChapterJ00–J99Diseases of the respiratory system
SectionJ09-J18Influenza and pneumonia
CategoryJ10Influenza due to other identified influenza virus
This CodeJ10.81Influenza due to other identified influenza virus with encephalopathy

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Encephalopathy caused by Influenza A virus
  • Encephalopathy caused by Influenza A virus subtype H1N1

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.

    • Influenza(bronchial) (epidemic) (respiratory (upper)) (unidentified influenza virus)
      • due to
        • identified influenza virus NEC
          • with
            • encephalopathy

Clinical ClassificationClinical

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

CCSR RSP003
Influenza
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR NVS020
Other nervous system disorders (neither hereditary nor degenerative)
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Flu

The flu, also called influenza, is a respiratory infection caused by viruses. Each year, millions of Americans get sick with the flu. Sometimes it causes mild illness. But it can also be serious or even deadly, especially for people over 65, newborn babies, and people with certain chronic illnesses.

The full article covers:

  • What is the flu?
  • What causes the flu?
  • What are the symptoms of the flu?
  • What other problems can the flu cause?
  • How is the flu diagnosed?
  • What are the treatments for the flu?
  • Can the flu be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert J10.81 to ICD-9-CMHistory

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

ICD-9-CM
487.8 Flu w manifestation NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About J10.81Overview

Is J10.81 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report influenza due to other identified influenza virus with encephalopathy on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does J10.81 group to?

When influenza due to other identified influenza virus with encephalopathy is the principal diagnosis on an inpatient stay, it groups to MS-DRG 865, 866, with relative weights from 0.8696 to 1.4983 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of J10.81?

Under the General Equivalence Mappings, influenza due to other identified influenza virus with encephalopathy converts to ICD-9-CM 487.8 (flu w manifestation NEC). 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.