2020 ICD-10-CM Diagnosis Code R50.81

Fever presenting with conditions classified elsewhere

    2016 2017 2018 2019 2020 Billable/Specific Code Manifestation Code
  • R50.81 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • The 2020 edition of ICD-10-CM R50.81 became effective on October 1, 2019.
  • This is the American ICD-10-CM version of R50.81 - other international versions of ICD-10 R50.81 may differ.
ICD-10-CM Coding Rules
  • R50.81 describes the manifestation of an underlying disease, not the disease itself.
Code First
Code First Help
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation. In most cases the manifestation codes will have in the code title, "in diseases classified elsewhere." Codes with this title are a component of the etiology/manifestation convention. The code title indicates that it is a manifestation code. "In diseases classified elsewhere" codes are never permitted to be used as first listed or principle diagnosis codes. They must be used in conjunction with an underlying condition code and they must be listed following the underlying condition.
  • underlying condition when associated fever is present, such as with:
  • leukemia (
    ICD-10-CM Diagnosis Code C91

    Lymphoid leukemia

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Type 1 Excludes
    • personal history of leukemia (Z85.6)
    ICD-10-CM Diagnosis Code C95

    Leukemia of unspecified cell type

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Type 1 Excludes
    • personal history of leukemia (Z85.6)
  • neutropenia (
    ICD-10-CM Diagnosis Code D70
    • D70 Neutropenia
      • D70.0 Congenital agranulocytosis
      • D70.1 Agranulocytosis secondary to cancer chemother...
      • D70.2 Other drug-induced agranulocytosis
      • D70.3 Neutropenia due to infection
      • D70.4 Cyclic neutropenia
      • D70.8 Other neutropenia
      • D70.9 Neutropenia, unspecified
  • sickle-cell disease (
    ICD-10-CM Diagnosis Code D57
    • D57 Sickle-cell disorders
      • D57.0 Hb-SS disease with crisis
        • D57.00 …… unspecified
        • D57.01 Hb-SS disease with acute chest syndrome
        • D57.02 Hb-SS disease with splenic sequestration
      • D57.1 Sickle-cell disease without crisis
      • D57.2 Sickle-cell/Hb-C disease
        • D57.20 …… without crisis
        • D57.21 Sickle-cell/Hb-C disease with crisis
          • D57.211 Sickle-cell/Hb-C disease with acute chest syn...
          • D57.212 Sickle-cell/Hb-C disease with splenic sequest...
          • D57.219 Sickle-cell/Hb-C disease with crisis, unspeci...
      • D57.3 Sickle-cell trait
      • D57.4 Sickle-cell thalassemia
        • D57.40 …… without crisis
        • D57.41 Sickle-cell thalassemia with crisis
          • D57.411 Sickle-cell thalassemia with acute chest synd...
          • D57.412 Sickle-cell thalassemia with splenic sequestr...
          • D57.419 Sickle-cell thalassemia with crisis, unspecif...
      • D57.8 Other sickle-cell disorders
        • D57.80 …… without crisis
        • D57.81 Other sickle-cell disorders with crisis
          • D57.811 Other sickle-cell disorders with acute chest ...
          • D57.812 Other sickle-cell disorders with splenic sequ...
          • D57.819 Other sickle-cell disorders with crisis, unsp...
The following code(s) above R50.81 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to R50.81:
  • R00-R99
    2020 ICD-10-CM Range R00-R99

    Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified

    • 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:
    • (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.
    Type 2 Excludes
    • abnormal findings on antenatal screening of mother (O28.-)
    • certain conditions originating in the perinatal period (P04-P96)
    • signs and symptoms classified in the body system chapters
    • signs and symptoms of breast (N63, N64.5)
    Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
  • R50
    ICD-10-CM Diagnosis Code R50

    Fever of other and unknown origin

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Type 1 Excludes
    • 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)
    Fever of other and unknown origin
Approximate Synonyms
  • Febrile neutropenia
  • Fever presenting with other condition
  • Neutropenic fever
  • Periodic fever aphthous-stomatitis pharyngitis adenitis syndrome
ICD-10-CM R50.81 is grouped within Diagnostic Related Group(s) (MS-DRG v37.0):
  • 864 Fever and inflammatory conditions

Convert R50.81 to ICD-9-CM

Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
Code annotations containing back-references to R50.81:
  • Use Additional: D70
    , D57
    ICD-10-CM Diagnosis Code D70


      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    • agranulocytosis
    • decreased absolute neurophile count (ANC)
    Type 1 Excludes
    • neutropenic splenomegaly (D73.81)
    • transient neonatal neutropenia (P61.5)
    Use Additional
    ICD-10-CM Diagnosis Code D57

    Sickle-cell disorders

      2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code
    Type 1 Excludes
    • other hemoglobinopathies (D58.-)
    Use Additional
    • code for any associated fever (R50.81)

Diagnosis Index entries containing back-references to R50.81:
  • Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor) R50.9
    ICD-10-CM Diagnosis Code R50.9

    Fever, unspecified

      2016 2017 2018 2019 2020 Billable/Specific Code
    Applicable To
    • Fever NOS
    • Fever of unknown origin [FUO]
    • Fever with chills
    • Fever with rigors
    • Hyperpyrexia NOS
    • Persistent fever
    • Pyrexia NOS
    • due to
      • conditions classified elsewhere R50.81
    • presenting with conditions classified elsewhere R50.81

ICD-10-CM Codes Adjacent To R50.81
R49.0 Dysphonia
R49.1 Aphonia
R49.2 Hypernasality and hyponasality
R49.21 Hypernasality
R49.22 Hyponasality
R49.8 Other voice and resonance disorders
R49.9 Unspecified voice and resonance disorder
R50 Fever of other and unknown origin
R50.2 Drug induced fever
R50.8 Other specified fever
R50.81 Fever presenting with conditions classified elsewhere
R50.82 Postprocedural fever
R50.83 Postvaccination fever
R50.84 Febrile nonhemolytic transfusion reaction
R50.9 Fever, unspecified
R51 Headache
R52 Pain, unspecified
R53 Malaise and fatigue
R53.0 Neoplastic (malignant) related fatigue
R53.1 Weakness
R53.2 Functional quadriplegia

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.