ICD 10 Codes Guide - Healthcare

Fever ICD 10

In this topic, let us look in to Fever ICD 10 classification along with examples.


Fever, medically known as pyrexia is a condition or a symptom that arises due to a temporary increase in body temperature above the normal. The normal body temperature falls between 97 F to 99 F, 98.6 F being the average and it is controlled by the “thermostat” of our body, the Hypothalamus. For adults, fever usually is not a cause of concern unless the body temperature rises to 103 F. However, fever in toddlers and infants need to be carefully watched as this can indicate a serious infection.

Increase in body temperature can be caused by a virus, a bacterial infection, heat exhaustion, malignant tumors, inflammatory conditions such as rheumatoid arthritis, certain immunizations and some medications.

When the cause of the fever cannot be identified even after extensive evaluation, the fever is classified as “fever of unknown origin”.

Fever ICD 10 Classification in the ICD-10 manual-

The fever of unknown origin is coded with the codes under the category- R50. This category also includes – persistent fever, fever with chills and rigor.

The most common underlying causes of fever are infections. In the ICD-10 manual alphabetic index the following infections are classified under fever-

(Note: T67.01 requires a placeholder and 7th digit additionally)

Fever ICD 10 Example 1

 A 22-year-old male patient was diagnosed with acute typhoid fever with meningitis. Code the appropriate ICD 10 code for the above example.

Answer: A01.01

Fever ICD 10 Example 2

A 25-year-old female patient presents with severe headache, cough and fever. She also has loss of appetite and weakness. Doctor sends for a blood test for pathological confirmation of suspected Typhoid. Results are expected in 2 days.  Code the appropriate ICD-10-CM code(s).

Answer: R51.9, R05, R50.9

(Since Typhoid is a suspected condition, only the symptoms are coded for the visit)

Fever ICD 10 Example 3

Mr. Joe, 45 years visits his Primary Care Physician for fever since a week. The fever rises and come down on and off. A blood test is ordered, and the results are positive for Dengue fever. Code the scenario.

Answer: A90

Fever ICD 10 Example 4

 A 27-year-old women who delivered a week ago was admitted with high fever. Code the appropriate ICD-10-CM codes for this diagnosis?

Answer: O86.4

Fever ICD 10 Example 5

 A 50-year-old man presents with severe abdominal pain, fever, vomiting and bloating sensation. On a CT scan, a perforated bowel with abscess is seen. The peritoneal fluid and blood cultures are positive for pseudomonas. The diagnoses are: perforated bowel, peritoneal abscess and sepsis due to pseudomonas. Assign the appropriate ICD 10 CM codes.

Answer: A41.52, K65.1, K63.1

(In this scenario, the fever is not coded as there are confirmed diagnoses mentioned at the end of the report.)

Question and Answer

Code the appropriate Fever ICD 10 CM code for the following diagnoses-

  1. Zika virus fever
  2. Cat-scratch fever
  3. South African tick-bite fever
  4. Rat-bite fever
  5. Mosquito-borne viral fever
  6. Indian tick typhus
  7. Oroya fever
  8. Murine (flea-borne) typhus
  9. Persistent fever
  10. Junin hemorrhagic fever
  11. Fever with chills
  12. Chills without fever
  13. Heat pyrexia, initial encounter
  14. Arboviral fever
  15. Plasmodium ovale malaria


  1. A92.5
  2. A28.1
  3. A68.1
  4. A25.9
  5. A92.9
  6. A77.1
  7. A44.0
  8. A75.2
  9. R50.9
  10. A96.0
  11. R50.9
  12. R68.83
  13. T67.01XA
  14. A94
  15. B53.0

Fill in the blanks.

  • Infection due to Coxiella burnetii is also known as _____________, __________________ and __________________ and the appropriate diagnosis code for these is _________.

(Answer: Q Fever, Nine-mile fever, Quadrilateral fever, A78)


  • The ICD-10-CM code A77.1 is applicable to _________, _____________, _____________, ___________, __________, ________, __________.

(Answer: Spotted fever due to Rickettsia conorii, African tick typhus, Boutonneuse fever, India tick typhus, Kenya tick typhus, Marseilles fever, Mediterranean tick fever)


  • Breakbone disease is another name for _______________.

(Answer: Dengue fever)


  • Assam fever is another name for _____________ and the ICD-10 code is _____________.

(Answer: Kala-azar, B55.0)