ICD-10 Code I30.9 – Acute pericarditis, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I30.9 – Acute pericarditis, unspecified
What it is
I30.9 identifies an acute inflammation of the pericardium when the record does not specify a cause or subtype. Use it for a new, short-term pericarditis diagnosis documented without further detail.
Clinical signs
Typical findings include sharp chest pain that may worsen with breathing or lying flat, and a pericardial friction rub on exam. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents acute pericarditis but does not identify infectious, autoimmune, post-injury, or other specified etiology. It also fits when the record simply states “acute pericarditis” or “pericarditis, unspecified.”
If later documentation names a specific type or cause, code the more specific diagnosis instead. Check documentation for associated conditions and whether the episode is acute rather than chronic or recurrent.
Do not use for
Do not use I30.9 for chronic, recurrent, or constrictive pericarditis, or when a documented cause supports a different code. Do not assign it if the chart clearly specifies another acute pericarditis category.
Coding tip
Look for the exact wording in the assessment; if the cause is named, code that specific form instead of the unspecified option.