ICD-10 Code A43 – Nocardiosis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A43 – Nocardiosis
What it is
A43 identifies nocardiosis, an infection caused by Nocardia species. It may affect the lungs, skin, or spread to other organs; use the code when documentation confirms this diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings include pulmonary symptoms, skin lesions, or evidence of disseminated infection, especially in patients with impaired immunity.
When to use this code
Use A43 when the provider documents nocardiosis, nocardial infection, or infection due to Nocardia without a more specific site code. It may apply to pulmonary, cutaneous, or disseminated disease if the record supports the diagnosis. Check documentation for the exact anatomic site and any additional organism details.
Do not use for
Do not use A43 for nonspecific bacterial infection or for other actinomycotic infections. If the record only says “rule out” or “possible” nocardiosis, check documentation before coding.
Coding tip
Verify whether the chart specifies pulmonary, cutaneous, or disseminated involvement, and code any documented site-specific manifestation when appropriate.