I00 — Rheumatic fever without heart involvement
Is I00 billable?
Yes — I00 is billable for FY2027. I00 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. I00 may be submitted for encounters from October 1, 2026 through September 30, 2027.
I00 at a glance
| Code | I00 |
|---|---|
| Description | Rheumatic fever without heart involvement |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does I00 group to?
I00 sits in MDC 08 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 545Connective Tissue Disorders with MCCmedical
- 546Connective Tissue Disorders with CCmedical
- 547Connective Tissue Disorders without CC/MCCmedical
How is I00 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to I00. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Fever › rheumatic (inanition) (of unknown origin) (persistent) (with chills) (with rigor)
- Pneumonia › rheumatic (acute) (double) (migratory) (purulent) (septic) (unresolved)
- Rheumatic › pneumonia (acute) (subacute)
- Erythema, erythematous › marginatum › inacute rheumatic fever (infectional) (inflammation)
- Pneumonia › in › rheumatic fever (acute) (double) (migratory) (purulent) (septic) (unresolved)
Excludes1 — never code together
The conditions below can never be reported together with I00 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Includes
Conditions classified to I00.
- arthritis, rheumatic, acute or subacute
Excludes2 — not included here — inherited from Chapter 9
The conditions below are not part of I00, but a patient may have both at the same time. When documentation supports it, I00 and the excluded code may both be reported.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- systemic connective tissue disorders (M30-M36)
- transient cerebral ischemic attacks and related syndromes (G45.-)
How long has I00 existed?
I00 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.
Which codes are confused with I00?
ICD-10-CM declares these codes mutually exclusive with I00 — exactly one of each pair can be correct for a given encounter.