ICD-10 Code J18.9 – Pneumonia, unspecified organism (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code J18.9 – Pneumonia, unspecified organism
What it is
J18.9 identifies pneumonia when the organism causing the infection is not specified in the record. Use it for a documented pneumonia diagnosis without a named bacterial, viral, or fungal cause.
Clinical signs
Clinical features vary; refer to documentation. Common findings include cough, fever, shortness of breath, chest discomfort, and imaging consistent with pneumonia, but the cause is not identified.
When to use this code
Use this code when the provider documents pneumonia and does not name the organism, or when the record supports pneumonia but the etiology remains unspecified. It is also appropriate when final documentation stays non-specific despite workup. Code the confirmed diagnosis as documented, not a suspected cause.
Do not use for
Do not use J18.9 if the organism is known and documented, such as bacterial or viral pneumonia. Do not use it for aspiration pneumonia or other specifically classified pneumonias.
Coding tip
Check the final provider note and discharge summary for a named organism before assigning J18.9.