ICD-10 Code I15 – Secondary Hypertension (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I15 – Secondary hypertension
What it is
Secondary hypertension is high blood pressure caused by an identifiable underlying condition rather than primary essential hypertension. Use this code when documentation links the elevated blood pressure to another disease process.
Clinical signs
Clinical features vary; refer to documentation. Patients may have persistent hypertension with findings related to the underlying cause, such as kidney, endocrine, or vascular disease.
When to use this code
Use I15 when the provider documents hypertension as secondary, caused by another condition, or when the chart clearly identifies a causal disorder. Code the underlying condition separately when instructed by the record and coding guidelines.
If the note only says hypertension without a cause, do not assume secondary hypertension. Check documentation for the specific etiology and any required combination coding.
Do not use for
Do not use I15 for essential or primary hypertension, or when the record does not support a secondary cause. Check documentation if the cause is unclear or not explicitly stated.
Coding tip
Link the hypertension to the documented underlying condition and verify whether additional codes are needed for the cause.