ICD-10-CM 2027
ICD-10 code for fever
Confirmed by the official ICD-10-CM index entry “chill (s) › with fever”. Page updated September 29, 2026.
About coding fever
The ICD-10-CM code for fever is R50.9 (Fever, unspecified). The official index lists 5 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on R50.9.
Within R50, choose R50.9 (Fever, unspecified) only when documentation doesn't support a more specific option: drug induced fever (R50.2) and other specified fever (R50.8).
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 864 (Fever and Inflammatory Conditions, relative weight 0.8551), in MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Related Fever codes
Common questions about fever ICD-10 codes
What is the ICD-10 code for fever?
- R50.9 — Fever, unspecified. More specific codes apply when the documentation supports them: R50.2, R50.81, R50.82, R50.83 and others below.
What is the ICD-10 code for drug induced fever?
- R50.2 — Drug induced fever.
What is the ICD-10 code for fever presenting with conditions classified elsewhere?
- R50.81 — Fever presenting with conditions classified elsewhere.
What is the ICD-10 code for postprocedural fever?
- R50.82 — Postprocedural fever.
What is the ICD-10 code for postvaccination fever?
- R50.83 — Postvaccination fever.
What is the ICD-10 code for febrile nonhemolytic transfusion reaction?
- R50.84 — Febrile nonhemolytic transfusion reaction.
Is R50.9 billable?
- Yes. R50.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can R50.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict R50.9 as a principal diagnosis.
Is R50.9 a CC or MCC?
- No. R50.9 is neither a CC nor an MCC under MS-DRG v44.0.