ICD-10 code for giant cell myocarditis

The ICD-10-CM code for giant cell myocarditis is I40.1 (Isolated myocarditis).

Within I40 (acute myocarditis), I40.1 is specifically for isolated myocarditis. Related codes cover infective myocarditis (I40.0), other acute myocarditis (I40.8) and unspecified (I40.9).

As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" 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), DRG 316 (Other Circulatory System Diagnoses without CC/MCC, relative weight 0.6677), DRG 974 (HIV with Major Related Condition with MCC, relative weight 3.0506), DRG 975 (HIV with Major Related Condition with CC, relative weight 1.3252) and DRG 976 (HIV with Major Related Condition without CC/MCC, relative weight 0.8124), in MDC 05 (Diseases and Disorders of the Circulatory System) and MDC 25 (Human Immunodeficiency Virus Infections), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.