ICD-10-CM 2027
ICD-10 code for mitral endocarditis
From the official ICD-10-CM alphabetic index entry “Endocarditis (chronic) (marantic) (nonbacterial) (thrombotic) (valvular) › mitral (chronic) (double) (fibroid) (heart) (inactive) (valve) (with chorea)”. Page updated September 29, 2026.
About coding mitral endocarditis
The ICD-10-CM code for mitral endocarditis is I05.9 (Rheumatic mitral valve disease, unspecified). The official index lists 14 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on I05.9.
Within I05, choose I05.9 (Rheumatic mitral valve disease, unspecified) only when documentation doesn't support a more specific option: rheumatic mitral stenosis (I05.0), rheumatic mitral insufficiency (I05.1), rheumatic mitral stenosis with insufficiency (I05.2) and other rheumatic mitral valve diseases (I05.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
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.
More specific mitral endocarditis codes (official index)
- with
- aortic (valve) disease I08.0 — Rheumatic disorders of both mitral and aortic valves
- with tricuspid (valve) disease I08.3 — Combined rheumatic disorders of mitral, aortic and tricuspid valves
- active or acute I01.1 — Acute rheumatic endocarditis
- with chorea (acute) (rheumatic) (Sydenham's) I02.0 — Rheumatic chorea with heart involvement
- rheumatic fever (conditions in I00)
- active
- inactive or quiescent (with chorea) I05.9 — Rheumatic mitral valve disease, unspecified
- tricuspid (valve) disease I08.1 — Rheumatic disorders of both mitral and tricuspid valves
- with aortic (valve) disease I08.3 — Combined rheumatic disorders of mitral, aortic and tricuspid valves
- active or acute I01.1 — Acute rheumatic endocarditis
- with chorea (acute) (rheumatic) (Sydenham's) I02.0 — Rheumatic chorea with heart involvement
- bacterial I33.0 — Acute and subacute infective endocarditis
- arteriosclerotic I34.89 — Other nonrheumatic mitral valve disorders
- nonrheumatic I34.89 — Other nonrheumatic mitral valve disorders
- acute or subacute I33.9 — Acute and subacute endocarditis, unspecified
- specified NEC I05.8 — Other rheumatic mitral valve diseases
Common questions about mitral endocarditis ICD-10 codes
What is the ICD-10 code for mitral endocarditis?
- I05.9 — Rheumatic mitral valve disease, unspecified. More specific codes apply when the documentation supports them: I08.0, I08.3, I01.1, I02.0 and others below.
What is the ICD-10 code for active or acute mitral endocarditis?
- I01.1 — Acute rheumatic endocarditis.
What is the ICD-10 code for arteriosclerotic mitral endocarditis?
- I34.89 — Other nonrheumatic mitral valve disorders.
What is the ICD-10 code for nonrheumatic mitral endocarditis?
- I34.89 — Other nonrheumatic mitral valve disorders.
Is I05.9 billable?
- Yes. I05.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I05.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I05.9 as a principal diagnosis.
Is I05.9 a CC or MCC?
- No. I05.9 is neither a CC nor an MCC under MS-DRG v44.0.