ICD-10 Code J11.00 – Influenza due to unidentified influenza virus with unspecified type of pneumonia (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code J11.00 – Influenza due to unidentified influenza virus with unspecified type of pneumonia
What it is
This code identifies influenza caused by an unidentified influenza virus when pneumonia is present, but the pneumonia type is not specified. Use it when the record confirms influenza and pneumonia without naming the virus subtype.
Clinical signs
Clinical features vary; refer to documentation. Typical records may note influenza-like illness with cough, fever, respiratory symptoms, and evidence of pneumonia on exam or imaging.
When to use this code
Use J11.00 when the clinician documents influenza with pneumonia and does not identify the influenza virus type. It also fits cases where pneumonia is documented as unspecified. If the record names a specific virus or different pneumonia type, check documentation before coding.
Do not use for
Do not use this code for influenza with bronchitis, other respiratory manifestations, or when pneumonia is not documented. Also avoid it if the influenza virus is identified and a more specific code applies.
Coding tip
Verify both influenza and pneumonia are documented, and confirm that the virus remains unidentified before assigning J11.00.