R50.9
Fever, unspecified
Billable FY2026 2025-10-01 → 2026-09-30
This is the unspecified option. 2 more
specific codes sit alongside it. Worth
checking whether the documentation supports one of them.
Exclusions 11 never code together
Instructional notes 16
R50.9code
Inclusion terms
- Fever NOS
- Fever of unknown origin [FUO]
- Fever with chills
- Fever with rigors
- Hyperpyrexia NOS
- Persistent fever
- Pyrexia NOS
R00-R99chapter
Notes
- This chapter includes symptoms, signs, abnormal results of clinical or other investigative procedures, and ill-defined conditions regarding which no diagnosis classifiable elsewhere is recorded.
- Signs and symptoms that point rather definitely to a given diagnosis have been assigned to a category in other chapters of the classification. In general, categories in this chapter include the less well-defined conditions and symptoms that, without the necessary study of the case to establish a final diagnosis, point perhaps equally to two or more diseases or to two or more systems of the body. Practically all categories in the chapter could be designated 'not otherwise specified', 'unknown etiology' or 'transient'. The Alphabetical Index should be consulted to determine which symptoms and signs are to be allocated here and which to other chapters. The residual subcategories, numbered .8, are generally provided for other relevant symptoms that cannot be allocated elsewhere in the classification.
- The conditions and signs or symptoms included in categories R00-R94 consist of:R00-R94
- (a) cases for which no more specific diagnosis can be made even after all the facts bearing on the case have been investigated;
- (b) signs or symptoms existing at the time of initial encounter that proved to be transient and whose causes could not be determined;
- (c) provisional diagnosis in a patient who failed to return for further investigation or care;
- (d) cases referred elsewhere for investigation or treatment before the diagnosis was made;
- (e) cases in which a more precise diagnosis was not available for any other reason;
- (f) certain symptoms, for which supplementary information is provided, that represent important problems in medical care in their own right.
Index entries leading here 11
- Temperature
- body, high (of unknown origin) R50.9
- Elevated, elevation
- body temperature (of unknown origin) R50.9
- Chill (s) R68.83
- with fever R50.9
- Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor) R50.9
- Inanition R64
- fever R50.9
- FUO (fever of unknown origin) R50.9
- High
- temperature (of unknown origin) R50.9
- Hyperpyrexia R50.9
- unknown origin R50.9
- Pyrexia (of unknown origin) R50.9
- persistent R50.9
- PUO (pyrexia of unknown origin) R50.9
- Rigors R68.89
- with fever R50.9
Alongside this code 2 same parent — R50
Medications 5
27 Fever drugs 11 Rheumatic Fever drugs 7 Typhoid Fever drugs 7 Blackwater Fever drugs 6 Relapsing Fever drugs
MED-RT files conditions by MeSH, which carves the world differently from ICD-10. These are name matches on this code's description, offered as candidates — not as an assertion that they are this code.
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.