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ICD-10-CM 2027 diagnosis code

R50.9Fever, unspecified

✓ Billable / specific

R50.9 is a valid, billable ICD-10-CM code for fever, unspecified. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Fever, ICD-10 code for FUO, ICD-10 code for PUO, ICD-10 code for Pyrexia.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About R50.9

R50.9 is the ICD-10-CM diagnosis code for fever, unspecified. It belongs to category R50 (fever of other and unknown origin), block R50-R69 (general symptoms and signs) and chapter 18 (symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

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.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 780.60 (fever, unspecified).

Coding notes

Applicable toConditions and synonyms classified to this code
  • Fever NOS
  • Fever of unknown origin [FUO]
  • Fever with chills
  • Fever with rigors
  • Hyperpyrexia NOS
  • Persistent fever
  • Pyrexia NOS

Notes that apply from higher levels

Instructions written at a parent level also apply to R50.9.

› From R50 Fever of other and unknown origin
Excludes1
  • 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)

Broader instructions also apply from Chapter 18: Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified.

Alphabetic index entries

17 entries

Terms in the official ICD-10-CM index that lead to R50.9.

Codes whose notes reference R50.9

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

MDC 18 · Infectious and Parasitic Diseases, Systemic or Unspecified Sites

ICD-9-CM equivalent

Converter →
  • 780.60Fever, unspecifiedapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about R50.9

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.

What DRG does R50.9 group to?

R50.9 is used in the MS-DRG v44.0 logic for MS-DRG 864 (Fever and Inflammatory Conditions). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for R50.9?

The CMS General Equivalence Mappings map R50.9 to ICD-9-CM 780.60.