I01 ICD-10-CM Code: Rheumatic fever with heart involvement

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for I01 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Coder workflow for I01

MedCoder structured workflow — derived from this code’s own official record

Before you code I01

1. I01 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

   ReviewI01.0, I01.1, I01.2, I01.8, I01.9

   See the relationships section · Guide: How to choose an ICD-10-CM code →

2. I01’s title joins a condition with an associated condition or complication. Confirm each component is documented. Where the classification presumes the link through the “with” convention, only a provider statement that the conditions are unrelated defeats it. A combination code is assigned only when it fully identifies the documented conditions; a required second code for the stage, type or manifestation is still reported when the notes ask for it (Guidelines I.B.9, I.A.15).

   Guide: Combination codes →

3. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with I01. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

   See the official tabular notes

Choose the right path

1. Does the documentation support one of the more specific codes beneath I01?
   Yes → Select that code and continue the checks below on its own page.
   No → I01 cannot be reported as written; query for the specificity its subcategory needs.

   ReviewI01.0, I01.1, I01.2, I01.8, I01.9

2. Does the documentation support a condition named in I01’s Excludes1 note?
   Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
   No → Continue.

Consider I01. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement

Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

The associated condition or complication

Whether the associated condition the title names is documented; the “with” convention presumes some links, and a provider statement that the conditions are unrelated defeats it (Guidelines I.A.15).

Official instructions as workflow

• Excludes1 — check before selecting I01(1 note)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with I01: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  See the official tabular notes · Guidelines I.A.12.a

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Indexed Clinical Terms (1)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

• Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor), rheumatic (active) (acute) (chronic) (subacute), active with heart involvement

Don’t confuse I01 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of I01 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• I05— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of chronic diseases of rheumatic origin unless rheumatic fever is also present or there is evidence of reactivation or activity of the rheumatic process. moves the case to I05; the two are not reported together unless documented as unrelated.

  Full comparison: I01 vs I05 →

• I09— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of chronic diseases of rheumatic origin unless rheumatic fever is also present or there is evidence of reactivation or activity of the rheumatic process. moves the case to I09; the two are not reported together unless documented as unrelated.

  Full comparison: I01 vs I09 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• Not billable as written — a more specific code is required: I01.0, I01.1, I01.2, I01.8, I01.9.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name I01 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes2 note: I51 — Complications and ill-defined descriptions of heart disease.

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Related Codes

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Fever”; these codes share that main term but sit in a different category of the Tabular List.

B52.9 — Plasmodium malariae malaria without complication (quartan), B53.0 — Plasmodium ovale malaria (Plasmodium ovale), B55.0 — Visceral leishmaniasis (Assam), B65.2 — Schistosomiasis due to Schistosoma japonicum (Katayama), B83.9 — Helminthiasis, unspecified (worm), B99.8 — Other infectious disease (infective, specified NEC), B99.9 — Unspecified infectious disease (infective), D70.9 — Neutropenia, unspecified (neutropenic), D86.89 — Sarcoidosis of other sites (uveoparotid), I00 — Rheumatic fever without heart involvement (rheumatic), I02.9 — Rheumatic chorea without heart involvement (rheumatic, with central nervous system involvement), I05.9 — Rheumatic mitral valve disease, unspecified (rheumatic, inactive or quiescent with, endocarditis, mitral), I06.9 — Rheumatic aortic valve disease, unspecified (rheumatic, inactive or quiescent with, endocarditis, aortic), I07.8 — Other rheumatic tricuspid valve diseases (rheumatic, inactive or quiescent with, endocarditis, tricuspid), I08.0 — Rheumatic disorders of both mitral and aortic valves (rheumatic, inactive or quiescent with, endocarditis, aortic, with mitraldisease), I09.0 — Rheumatic myocarditis (rheumatic, inactive or quiescent with, myocarditis, myocardial degeneration), I09.1 — Rheumatic diseases of endocardium, valve unspecified (rheumatic, inactive or quiescent with, endocarditis), I09.2 — Chronic rheumatic pericarditis (rheumatic, inactive or quiescent with, pericarditis), I09.81 — Rheumatic heart failure (rheumatic, inactive or quiescent with, heart failure), I09.89 — Other specified rheumatic heart diseases (rheumatic, inactive or quiescent with, heart disease NEC), +109 more

Contextual Map

Every relationship of I01 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run I01 with these 6 related codes in Claim Check

Hierarchy

• I00-I99 — Chapter 9: Diseases of the Circulatory System (I00-I99) (I00-I99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• I00-I02 — Acute rheumatic fever[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Excludes1

• I05 — Rheumatic mitral valve diseases[Excludes1]: “chronic diseases of rheumatic origin (I05-I09) unless rheumatic fever is also present or there is evidence of reactivation or activity of the rheumatic process.”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I06 — Rheumatic aortic valve diseases[Excludes1]: “chronic diseases of rheumatic origin (I05-I09) unless rheumatic fever is also present or there is evidence of reactivation or activity of the rheumatic process.”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I07 — Rheumatic tricuspid valve diseases[Excludes1]: “chronic diseases of rheumatic origin (I05-I09) unless rheumatic fever is also present or there is evidence of reactivation or activity of the rheumatic process.”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I08 — Multiple valve diseases[Excludes1]: “chronic diseases of rheumatic origin (I05-I09) unless rheumatic fever is also present or there is evidence of reactivation or activity of the rheumatic process.”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I09 — Other rheumatic heart diseases[Excludes1]: “chronic diseases of rheumatic origin (I05-I09) unless rheumatic fever is also present or there is evidence of reactivation or activity of the rheumatic process.”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes

• I51 — Complications and ill-defined descriptions of heart disease[Excludes2]: “heart disease specified as rheumatic (I00-I09)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Index entries

• Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor), rheumatic (active) (acute) (chronic) (subacute), active with heart involvement[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

• I01.0 — Acute rheumatic pericarditis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• I01.1 — Acute rheumatic endocarditis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• I01.2 — Acute rheumatic myocarditis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• I01.8 — Other acute rheumatic heart disease[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• I01.9 — Acute rheumatic heart disease, unspecified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to I01 in its code family, with their registry titles.

• I01.0 — Acute rheumatic pericarditis
• I01.1 — Acute rheumatic endocarditis
• I01.2 — Acute rheumatic myocarditis
• I01.8 — Other acute rheumatic heart disease
• I01.9 — Acute rheumatic heart disease, unspecified