ICD-9-CM Diagnosis Code 420.99
Diagnosis Code: 420.99 (Raw: 42099)
Description: Other acute pericarditis
Classification: International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM)
Fiscal Year: 2026 Reference
CMS Section 111 Status: Valid for reporting.
Overview & Historical Usage
ICD-9-CM code 420.99 is designated for Other acute pericarditis. While superseded by ICD-10 for current healthcare encounters, it remains a recognized reference code for CMS Section 111 reporting, legacy claims adjudication, and historical clinical data analysis.
