Influenza ICD-10 code
The ICD-10-CM code for influenza is J11.1 — influenza due to unidentified influenza virus with other respiratory manifestations. It is billable and valid for submission on a claim. There are 16 related codes, and which one you use depends on what the documentation supports.
Also written as flu, the flu, seasonal influenza.
The mistake coders make here
J11.- is influenza where the virus was NOT identified, and it is the right code for the ordinary case. J10.- requires a laboratory-identified influenza virus, and J09.- is reserved for identified novel influenza A. A positive rapid antigen test does not on its own move you from J11 to J10 unless the provider documents the identification.
All ICD-10-CM codes for influenza
9 of 16 are billable. Green means you can submit it as-is.
| Code | Use it when |
|---|---|
| J11.1 | Influenza due to unidentified influenza virus with other respiratory manifestations |
| J11.00 | Influenza due to unidentified influenza virus with unspecified type of pneumonia |
| J10.1 | Influenza due to other identified influenza virus with other respiratory manifestations |
| J10.00 | Influenza due to other identified influenza virus with unspecified type of pneumonia |
| J09.X2 | Influenza due to identified novel influenza A virus with other respiratory manifestations |
| J11 | Influenza due to unidentified influenza virusnot billable on its own |
| J10 | Influenza due to other identified influenza virusnot billable on its own |
| J09 | Influenza due to certain identified influenza virusesnot billable on its own |
| J11.0 | Influenza due to unidentified influenza virus with pneumonianot billable on its own |
| J10.0 | Influenza due to other identified influenza virus with pneumonianot billable on its own |
| J10.82 | Influenza due to other identified influenza virus with myocarditis |
| J10.81 | Influenza due to other identified influenza virus with encephalopathy |
| J11.89 | Influenza due to unidentified influenza virus with other manifestations |
| J11.8 | Influenza due to unidentified influenza virus with other manifestationsnot billable on its own |
| J10.89 | Influenza due to other identified influenza virus with other manifestations |
| J10.8 | Influenza due to other identified influenza virus with other manifestationsnot billable on its own |
J09, J10 and J11 are separated by what was identified, not by severity
This is the whole of the choice and it is easy to get backwards. J11.- is influenza due to unidentified influenza virus — the default, and correct for the great majority of encounters, including ones where the patient clearly has flu. J10.- is influenza due to other identified influenza virus, meaning a specific seasonal influenza virus was identified. J09.- is narrower still: influenza due to identified novel influenza A virus, which is the avian and pandemic-strain category and not somewhere to reach without explicit documentation. Severity does not enter into it; a severely ill patient with no virus identified is still J11.-.
The fourth and fifth characters carry the manifestation
Each block subdivides the same way, by what the influenza did. J11.1 is influenza with other respiratory manifestations, which is the ordinary uncomplicated flu and the most-assigned code in the set. J11.00 is influenza with unspecified type of pneumonia and J11.08 with other specified pneumonia — and where influenza pneumonia is coded, the pneumonia is not additionally coded from J18.-. J11.2 through J11.89 cover gastrointestinal, encephalopathic and other manifestations. Assigning J11.1 to a patient with documented influenza pneumonia understates the admission.
Common questions
- What is the ICD-10 code for influenza, unspecified?
- J11.1, influenza due to unidentified influenza virus with other respiratory manifestations, is the code for ordinary uncomplicated influenza where no virus was identified. Note that 'unspecified' in the query usually means the virus was not identified rather than that the manifestation is unknown — if the manifestation genuinely is not documented, J11.1 still applies as the other-respiratory default.
- Does a positive flu test mean I code J10 instead of J11?
- Not by itself. J10.- requires the influenza virus to have been identified and the provider to have documented that identification. A rapid antigen result in the chart, without the provider linking it to the diagnosis, does not move the code out of J11.-. Where it matters and the documentation is ambiguous, that is a query.
- How is influenza with pneumonia coded?
- Within the influenza code itself, not as two diagnoses. J11.00 is influenza with unspecified type of pneumonia and J11.08 is influenza with other specified pneumonia; the equivalents exist under J10 and J09. Adding a separate J18.- code alongside one of these duplicates the pneumonia.