Alphabetic Index FY2027

J11.81

Influenza due to unidentified influenza virus with encephalopathy

FY2027Chapter 10: Diseases of the respiratory system/J09–J18 Influenza and pneumonia

BillableComplete code, valid to report
Care settingsHome Health Primary · MMTA - Respiratory

J11.81 (also written J1181) is a billable ICD-10-CM diagnosis code for influenza due to unidentified influenza virus with encephalopathy. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 8 codes in category J11 (Influenza due to unidentified influenza virus). The Alphabetic Index lists it under 1 entry. Its coding notes include a Use additional code instruction and 18 Excludes2 entries.

Guidelines tip

From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.

J09 and J10 are for confirmed cases. If the provider records suspected, possible or probable influenza, J11 is assigned.

Guidelines I.C.10.cInfluenza: identified and unidentified virusesRead the official text

Use additional code

Add the listed code as a secondary code, if known.

Also from chapter/block level (8 notes)
Inherited from J09–J18 Influenza and pneumonia
  • code, if applicable, to identify resistance to antimicrobial drugs (Z16.-)
Inherited from Chapter 10 Diseases of the respiratory system
  • code, where applicable, to identify:
    • exposure to environmental tobacco smoke (Z77.22)
    • exposure to tobacco smoke in the perinatal period (P96.81)
    • history of tobacco dependence (Z87.891)
    • occupational exposure to environmental tobacco smoke (Z57.31)
    • tobacco dependence (F17.-)
    • tobacco use (Z72.0)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (18 notes)
Inherited from J09–J18 Influenza and pneumonia
  • allergic or eosinophilic pneumonia (J82)
  • aspiration pneumonia NOS (J69.0)
  • meconium pneumonia (P24.01)
  • neonatal aspiration pneumonia (P24.-)
  • pneumonia due to solids and liquids (J69.-)
  • congenital pneumonia (P23.9)
  • lipid pneumonia (J69.1)
  • rheumatic pneumonia (I00)
  • ventilator associated pneumonia (J95.851)
Inherited from Chapter 10 Diseases of the respiratory system
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • smoke inhalation (T59.81-)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

Home Health Primary

Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Respiratory clinical group.

Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026

Inclusion terms

Conditions classified to this code.

This code
  • Influenzal encephalopathy NOS

Notes

Also from chapter/block level (1 note)
Inherited from Chapter 10 Diseases of the respiratory system
  • When a respiratory condition is described as occurring in more than one site and is not specifically indexed, it should be classified to the lower anatomic site (e.g. tracheobronchitis to bronchitis in J40).

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 1 entry