2026 ICD-10-CM Diagnosis Code I30.0Acute nonspecific idiopathic pericarditis

ICD-10-CM Codes›I00–I99›I30-I5A›I30

ICD-10-CM I30.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I30.0 is a billable ICD-10-CM diagnosis code for acute nonspecific idiopathic pericarditis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 314 through 316. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 16 closely related codes. Coders also document this condition as acute idiopathic pericarditis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Pericarditis and pericardial disease.

Code Identity

ICD-10-CM Code
I30.0
Billable Status
Yes — Valid for Submission
Code Describes
Acute nonspecific idiopathic pericarditis
Short Description
Acute nonspecific idiopathic pericarditis
Same as the full description in the CMS dataset.
Parent Code
I30
Acute pericarditis

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI30-I5AOther forms of heart disease
CategoryI30Acute pericarditis
This CodeI30.0Acute nonspecific idiopathic pericarditis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute idiopathic pericarditis
  • Idiopathic recurrent pericarditis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR CIR006
Pericarditis and pericardial disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Acute Pericarditis

    acute inflammation of the pericardium.

  • Acute Pericarditis Related to COVID-19|Acute pericarditis

    acute pericarditis in a patient with probable or confirmed acute covid-19.

Patient EducationClinical

Pericardial Disorders

The pericardium is a membrane, or sac, that surrounds your heart. It holds the heart in place and helps it work properly. Problems with the pericardium include:

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert I30.0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
420.91 Ac idiopath pericarditis
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About I30.0Overview

What is the ICD-10 code for acute nonspecific idiopathic pericarditis?

The ICD-10-CM code for acute nonspecific idiopathic pericarditis is I30.0 (sometimes written as I300). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is I30.0 (Acute pericarditis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report acute nonspecific idiopathic pericarditis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I30.0 group to?

When acute nonspecific idiopathic pericarditis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 314, 315, 316, with relative weights from 0.6821 to 2.0852 depending on complications. Higher weights mean higher Medicare reimbursement.

Is I30.0 a CC or MCC?

CMS lists I30.0 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 16 closely related codes in its exclusion list.

What is the ICD-9 equivalent of I30.0?

Under the General Equivalence Mappings, acute nonspecific idiopathic pericarditis converts to ICD-9-CM 420.91 (ac idiopath pericarditis). The mapping is a direct match.