R50.9 — Fever, unspecified
R50.9 is a billable, specific ICD-10-CM code for fever, unspecified. It is valid for submission on a claim.
Inclusion terms
Alternative wordings a physician may use in the chart for this same code.
- Fever NOS
- Fever of unknown origin [FUO]
- Fever with chills
- Fever with rigors
- Hyperpyrexia NOS
- Persistent fever
- Pyrexia NOS
Other codes that can never be billed with R50.9
These codes carry an Excludes1 note pointing at R50.9. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading R50.9 alone.
- R68.83Chills (without fever)
Risk adjustment
R50.9 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
Medicare coverage
R50.9 is named in 27 Medicare coverage policies — 27 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A55326Billing and Coding: Zika Virus Testing by PCR and ELISA Methods
- A56421Billing and Coding: CT of the Abdomen and Pelvis
- A56476Billing and Coding: Cardiac Radionuclide Imaging
- A56625Billing and Coding: Echocardiography
How R50.9 is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to R50.9.
- Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
- FUO(fever of unknown origin)
- Hyperpyrexia
- PUO(pyrexia of unknown origin)
- Pyrexia(of unknown origin)
- Chill›with fever
- Elevated, elevation›body temperature(of unknown origin)
- Fever›ephemeral(of unknown origin)
- Fever›persistent(of unknown origin)
- Fever›unknown origin
- High›temperature(of unknown origin)
- Hyperpyrexia›unknown origin
Related codes at this level
Codes that share R50. If R50.9 is not quite right, the correct code is usually one of these.
Questions about R50.9
- Is R50.9 a billable ICD-10-CM code?
- Yes. R50.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does R50.9 sit in the tabular list?
- Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99), in the block General symptoms and signs (R50-R69).