ICD-10-CM 2027
ICD-10 code for coxsackie endocarditis
From the official ICD-10-CM alphabetic index entry “Endocarditis (chronic) (marantic) (nonbacterial) (thrombotic) (valvular) › Coxsackie”. Page updated September 29, 2026.
About coding coxsackie endocarditis
The ICD-10-CM code for coxsackie endocarditis is B33.21 (Viral endocarditis).
Within B33.2 (viral carditis), B33.21 is specifically for viral endocarditis. Related codes cover unspecified (B33.20), myocarditis (B33.22), pericarditis (B33.23) and cardiomyopathy (B33.24).
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 306 (Cardiac Congenital and Valvular Disorders with MCC, relative weight 1.546) and DRG 307 (Cardiac Congenital and Valvular Disorders without MCC, relative weight 0.9148), 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.
Common questions about coxsackie endocarditis ICD-10 codes
What is the ICD-10 code for coxsackie endocarditis?
- B33.21 — Viral endocarditis.
Is B33.21 billable?
- Yes. B33.21 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can B33.21 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict B33.21 as a principal diagnosis.
Is B33.21 a CC or MCC?
- B33.21 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.