I31.9 Disease of pericardium, unspecified

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• Pericarditis (chronic) NOS

Applies from I31 Other diseases of pericardium

Excludes1 (never code together)

• diseases of pericardium specified as rheumatic (I09.2)
• postcardiotomy syndrome (I97.0)
• traumatic injury to pericardium (S26.-)

MS-DRG index

Defines the logic of DRG(s) 314-316 in MDC 05.

Approximate ICD-9-CM (GEMs)

• 423.9 Unspecified disease of pericardium (approximate)

Code annotations containing back-references to I31.9

Back-references to I31

• Type 1 Excludes: I09.2 Chronic rheumatic pericarditis ("chronic pericarditis not specified as rheumatic (I31.-)")

Diagnosis Index entries for I31.9

• Pericarditis (with decompensation) (with effusion)
• Pericarditis (with decompensation) (with effusion) › chronic (nonrheumatic)

Nearby codes

• I31.3 Pericardial effusion (noninflammatory)
• I31.31 Malignant pericardial effusion in diseases classified elsewhere
• I31.39 Other pericardial effusion (noninflammatory)
• I31.4 Cardiac tamponade
• I31.8 Other specified diseases of pericardium
• I31.9 Disease of pericardium, unspecified (this code)