R50.9

Billable

ChapterR00–R99

Ranksubcategory

Official Description

Fever, unspecified

Metadata & Insights

•2026 ICD-10-CM Edition - Effective October 1, 2025.
•Billable/specific code (valid for reimbursement).
•Chapter 18: Symptoms, Signs and Abnormal Clinical and Laboratory Findings (R00-R99).

Instructional Notes

Includes

Fever NOS
Fever of unknown origin [FUO]
Fever with chills
Fever with rigors
Hyperpyrexia NOS
Persistent fever
Pyrexia NOS

General instructions are available for the parent sections:

View CH18 Notes View R50 Notes

Clinical Hierarchy

CH18Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)

R50-R69General symptoms and signs (R50-R69)

R50Fever of other and unknown origin

R50.9Fever, unspecified

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to R50.9:

categoryR50

Fever of other and unknown origin

View context instructions

chapterCH18

Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)

View context instructions

Alphabetic Index Mentions

These are Diagnosis Index lookup paths that route to R50.9. Use them as entry terms for search, then confirm final coding instructions in the Tabular List and notes above.

17 raw paths

Chill (s)1 unique routes

with fever→R50.9

Elevated, elevation1 unique routes

body temperature (of unknown origin)→R50.9

Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor)5 unique routes

Direct index entry→R50.9

ephemeral (of unknown origin)→R50.9

intermittent (bilious)

of unknown origin→R50.9

persistent (of unknown origin)→R50.9

unknown origin→R50.9