ICD-10-CM 2027
ICD-10 code for rheumatic fever
From the official ICD-10-CM alphabetic index entry “Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor) › rheumatic (active) (acute) (chronic) (subacute)”. Page updated September 29, 2026.
About coding rheumatic fever
The ICD-10-CM code for rheumatic fever is I00 (Rheumatic fever without heart involvement). The official index lists 17 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on I00.
Don't report I00 together with the conditions in its Excludes1 note: rheumatic fever with heart involvement (I01.0-I01.9).
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 545 (Connective Tissue Disorders with MCC, relative weight 2.3892), DRG 546 (Connective Tissue Disorders with CC, relative weight 1.1745) and DRG 547 (Connective Tissue Disorders without CC/MCC, relative weight 0.7526), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), 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 rheumatic fever codes (official index)
- with central nervous system involvement I02.9 — Rheumatic chorea without heart involvement
- active with heart involvement I01 — Rheumatic fever with heart involvement
- inactive or quiescent with
- cardiac hypertrophy I09.89 — Other specified rheumatic heart diseases
- carditis I09.9 — Rheumatic heart disease, unspecified
- endocarditis I09.1 — Rheumatic diseases of endocardium, valve unspecified
- aortic (valve) I06.9 — Rheumatic aortic valve disease, unspecified
- with mitral (valve) disease I08.0 — Rheumatic disorders of both mitral and aortic valves
- mitral (valve) I05.9 — Rheumatic mitral valve disease, unspecified
- with aortic (valve) disease I08.0 — Rheumatic disorders of both mitral and aortic valves
- pulmonary (valve) I09.89 — Other specified rheumatic heart diseases
- tricuspid (valve) I07.8 — Other rheumatic tricuspid valve diseases
- heart disease NEC I09.89 — Other specified rheumatic heart diseases
- heart failure (congestive) (conditions in category I50.) I09.81 — Rheumatic heart failure
- left ventricular failure (conditions in I50.1-I50.4-) I09.81 — Rheumatic heart failure
- myocarditis, myocardial degeneration (conditions in I51.4) I09.0 — Rheumatic myocarditis
- pancarditis I09.9 — Rheumatic heart disease, unspecified
- pericarditis I09.2 — Chronic rheumatic pericarditis
Don't confuse with (Excludes1 for I00)
Common questions about rheumatic fever ICD-10 codes
What is the ICD-10 code for rheumatic fever?
- I00 — Rheumatic fever without heart involvement. More specific codes apply when the documentation supports them: I02.9, I01, I09.89, I09.9 and others below.
What is the ICD-10 code for active with heart involvement rheumatic fever?
- I01 — Rheumatic fever with heart involvement (header code; choose a more specific subcode).
Is I00 billable?
- Yes. I00 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I00 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I00 as a principal diagnosis.
Is I00 a CC or MCC?
- No. I00 is neither a CC nor an MCC under MS-DRG v44.0.