I31.31Malignant pericardial effusion in diseases classified elsewhere

I31.31 is the ICD-10-CM diagnosis code for malignant pericardial effusion in diseases classified elsewhere. It belongs to category I31 (other diseases of pericardium), block I30-I5A (other forms of heart disease) and chapter 9 (diseases of the circulatory system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within I31.3 (pericardial effusion (noninflammatory)), I31.31 is specifically for malignant pericardial effusion in diseases classified elsewhere. Related codes cover other pericardial effusion (noninflammatory) (I31.39).

Code first: underlying neoplasm (C00-D49).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 314 (Other Circulatory System Diagnoses with MCC, relative weight 2.0873), DRG 315 (Other Circulatory System Diagnoses with CC, relative weight 0.9508) and DRG 316 (Other Circulatory System Diagnoses without CC/MCC, relative weight 0.6677), in MDC 05 (Diseases and Disorders of the Circulatory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It is a manifestation code, so it describes the effect of an underlying disease and can't be the principal diagnosis. Code the underlying condition first.

It was added in FY2023, effective October 1, 2022.