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R50.9

✓ Billable

Fever, unspecified

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

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Also Known As

Fever NOSFever of unknown origin [FUO]Fever with chillsFever with rigorsHyperpyrexia NOSPersistent feverPyrexia NOS

❌ Excludes1

inherited from R50

Rules from parent category R50: Fever of other and unknown origin

  • • 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)

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Code Information

CodeR50.9
BillableYes
ParentR50
CategorySymptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)
Excludes17 rule(s)
Excludes20 note(s)

Data Source

CMS ICD-10-CM 2026 Tabular List

Updated October 1, 2025 (FY2026)