ICD-10 Code I39 – Endocarditis and heart valve disorders in diseases classified elsewhere (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I39 – Endocarditis and heart valve disorders in diseases classified elsewhere
What it is
Code I39 identifies endocarditis or heart valve disease that is caused by another underlying condition. You use it when the valve or endocardial problem is documented as secondary to a disease classified elsewhere.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include evidence of valve involvement or endocardial infection, but the record should clearly link the condition to an underlying disease.
When to use this code
Use I39 when the provider states that endocarditis or a heart valve disorder is due to another condition and the documentation supports that relationship. Code the underlying disease first when required by ICD-10-CM rules. If the cause is not specified, check documentation before assigning this code.
Do not use for
Do not use I39 for primary endocarditis or valve disorders without an “in diseases classified elsewhere” linkage. Also avoid it when the chart does not identify a causal underlying condition.
Coding tip
Confirm the documented cause and sequence the underlying condition correctly before assigning I39.