ICD10BillableValid for clinical use

ICD-10 Code J11.81: Influenza due to unidentified influenza virus with encephalopathy

J11.81 is a billable ICD-10 diagnosis code used to classify Influenza due to unidentified influenza virus with encephalopathy in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the respiratory system (J00-J99).

Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the respiratory system (J00-J99).

When is it used?

  • May be used when a clinician documents influenza due to unidentified influenza virus with encephalopathy in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter
10Diseases of the respiratory system (J00-J99)
block
J09-J18Influenza and pneumonia
category
J11Influenza due to unidentified influenza virus
category
J11.8Influenza due to unidentified influenza virus with other manifestations
currentJ11.8

Official coding notes

Inclusion terms
  • Influenzal encephalopathy NOS

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

PulmonologistGeneral Physician

Coverage-related procedures and services

CPT 87801high
INFECTIOUS AGENT DETECTION BY NUCLEIC ACID (DNA OR RNA), MULTIPLE ORGANISMS; AMPLIFIED PROBE(S) TECHNIQUE
Source: CMS coverage guidance
CPT 87631high
INFECTIOUS AGENT DETECTION BY NUCLEIC ACID (DNA OR RNA); RESPIRATORY VIRUS (EG, ADENOVIRUS, INFLUENZA VIRUS, CORONAVIRUS, METAPNEUMOVIRUS, PARAINFLUENZA VIRUS, RESPIRATORY SYNCYTIAL VIRUS, RHINOVIRUS), INCLUDES MULTIPLEX REVERSE TRANSCRIPTION, WHEN PERFORMED, AND MULTIPLEX AMPLIFIED PROBE TECHNIQUE, MULTIPLE TYPES OR SUBTYPES, 3-5 TARGETS
Source: CMS coverage guidance
CPT 87636high
INFECTIOUS AGENT DETECTION BY NUCLEIC ACID (DNA OR RNA); SEVERE ACUTE RESPIRATORY SYNDROME CORONAVIRUS 2 (SARS-COV-2) (CORONAVIRUS DISEASE [COVID-19]) AND INFLUENZA VIRUS TYPES A AND B, MULTIPLEX AMPLIFIED PROBE TECHNIQUE
Source: CMS coverage guidance
CPT 87637high
INFECTIOUS AGENT DETECTION BY NUCLEIC ACID (DNA OR RNA); SEVERE ACUTE RESPIRATORY SYNDROME CORONAVIRUS 2 (SARS-COV-2) (CORONAVIRUS DISEASE [COVID-19]), INFLUENZA VIRUS TYPES A AND B, AND RESPIRATORY SYNCYTIAL VIRUS, MULTIPLEX AMPLIFIED PROBE TECHNIQUE
Source: CMS coverage guidance
CPT 70460high
COMPUTED TOMOGRAPHY, HEAD OR BRAIN; WITH CONTRAST MATERIAL(S)
Source: CMS coverage guidance
CPT 70450high
COMPUTED TOMOGRAPHY, HEAD OR BRAIN; WITHOUT CONTRAST MATERIAL
Source: CMS coverage guidance

Coding guidelines

Common synonyms

Influenza due to unidentified influenza virus with encephalopathy

Frequently asked questions

Code details

CodeJ11.81
SystemICD10
Display nameInfluenza due to unidentified influenza virus with encephalopathy
ChapterDiseases of the respiratory system (J00-J99)
BlockInfluenza and pneumonia

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Influenza(bronchial) (epidemic) (respiratory (upper)) (unidentified influenza virus)

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.

ICD-10 Code J11.81 for Influenza due to unidentified influenza virus with encephalopathy | HealthAssure