2026 ICD-10-CM Diagnosis Code R50Fever of other and unknown origin

ICD-10-CM Codes›R00–R99›R50-R69›R50

ICD-10-CM R50
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R50 is a non-billable ICD-10-CM category code for fever of other and unknown origin, so it cannot be submitted on claims. Use a more specific code from this category instead, such as R50.2, R50.81, R50.82, and R50.83. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established.

Code Identity

ICD-10-CM Code
R50
Billable Status
No — Non-Billable Category
Code Describes
Fever of other and unknown origin
Chapter
R50-R69
General symptoms and signs

Code Classification

ChapterR00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
SectionR50-R69General symptoms and signs
CategoryR50Fever of other and unknown origin
This CodeR50Fever of other and unknown origin

Specific Coding for Fever of other and unknown originOverview

Non-specific codes like R50 require more characters. Use one of these billable codes instead:

  • Use R50.2 for Drug induced fever

  • R50.8 for Other specified fever

  • Use R50.81 for Fever presenting with conditions classified elsewhere

  • Use R50.82 for Postprocedural fever

  • Use R50.83 for Postvaccination fever

  • Use R50.84 for Febrile nonhemolytic transfusion reaction

  • Use R50.9 for Fever, unspecified

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Type 1 Excludes

  • chills without fever R68.83
  • febrile convulsions R56.0
  • fever of unknown origin during labor O75.2
  • fever of unknown origin in newborn P81.9
  • hypothermia due to illness R68.0
  • malignant hyperthermia due to anesthesia T88.3
  • puerperal pyrexia NOS O86.4

Patient EducationClinical

Fever

A fever is a body temperature that is higher than normal. A normal temperature can vary from person to person, but it is usually around 98.6 °F (37 °C). A fever is not a disease. It is usually a sign that your body is trying to fight an illness or infection.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About R50Overview

Is R50 (Fever of other and unknown origin) a billable code?

No. This is a category header that groups the codes for fever of other and unknown origin, and headers cannot be submitted on claims. Claims for fever of other and unknown origin need a more specific code from this category, such as R50.2, R50.81, and R50.82.

Can R50 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the fever of other and unknown origin is established, that condition takes the principal position instead.