ICD-10 Code J11.1 – Influenza due to unidentified influenza virus with other respiratory manifestations (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code J11.1 – Influenza due to unidentified influenza virus with other respiratory manifestations
What it is
This code identifies influenza when the virus is not specified and the patient has respiratory manifestations beyond a simple flu syndrome. Use it when the record documents influenza with additional respiratory involvement, but the exact virus is not identified.
Clinical signs
Clinical features vary; refer to documentation. Common respiratory findings may include cough, sore throat, nasal symptoms, or other lower or upper respiratory complaints noted by the clinician.
When to use this code
Use J11.1 when the provider documents influenza with other respiratory manifestations and does not identify the influenza virus type. This is appropriate for confirmed flu cases with respiratory involvement, even when the organism is listed as unidentified. If the record only says “influenza” without respiratory details, check documentation before coding.
Do not use for
Do not use this code for influenza with gastrointestinal symptoms alone or for influenza caused by an identified virus type. If the documentation supports a different influenza category, choose the more specific code.
Coding tip
Review the note for both the virus status and the documented manifestations before assigning J11.1.