ICD-10 Code A43.9 – Nocardiosis, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A43.9 – Nocardiosis, unspecified
What it is
A43.9 identifies nocardiosis when the specific site or form is not documented. Use it for infection caused by Nocardia species when the record only states “nocardiosis, unspecified.”
Clinical signs
Clinical features vary; refer to documentation. Nocardiosis may present as pulmonary, cutaneous, or disseminated infection, often with fever, cough, skin lesions, or neurologic findings.
When to use this code
Use A43.9 when the diagnosis is confirmed or documented as nocardiosis, but the provider does not specify the organ system or clinical form. It also fits when the note lacks enough detail for a more specific nocardiosis code. Check documentation before assigning a site-specific code.
Do not use for
Do not use this code for suspected nocardiosis without a confirmed diagnosis. If the record identifies a specific site or manifestation, code that more precise category instead.
Coding tip
Query for the infection site or form if the record says only “nocardiosis” and supports a more specific code.