ICD-10 Code for Fever
Also indexed as (inanition) (of unknown origin) (persistent) (with chills) (with rigor)
The ICD-10-CM code for fever is R50.9 — Fever, unspecified. This is the code the Alphabetic Index gives for fever with no further qualifier, valid for FY2027 (October 1, 2026 – September 30, 2027).
BillableUnspecified
R50.9 is billable but unspecified. If the documentation names a type, site or cause, one of the more specific codes below is likely expected.
Which fever code should you use?
The Alphabetic Index lists 130 codes under Fever. Which one applies depends on the qualifier documented in the record — the type, site, cause, or associated condition. Find the qualifier below, then verify the code in the Tabular List before using it.
By type
| abortus | A23.1 | Brucellosis due to Brucella abortus | |
| Aden | A90 | Dengue fever [classical dengue] | |
| African tick bite | A77.8 | Other spotted fevers | |
| African tick-borne | A68.1 | Tick-borne relapsing fever | |
| aphthous | B08.8 | Other specified viral infections characterized by skin and mucous membrane lesions | |
| arbovirus, arboviral | A94 | Unspecified arthropod-borne viral fever | |
| Argentinian hemorrhagic | A96.0 | Junin hemorrhagic fever | |
| Assam | B55.0 | Visceral leishmaniasis | |
| Australian Q | A78 | Q fever | |
| Bangkok hemorrhagic | A91 | Dengue hemorrhagic fever | |
| Barmah forest | A92.8 | Other specified mosquito-borne viral fevers | |
| Bartonella | A44.0 | Systemic bartonellosis | |
| bilious, hemoglobinuric | B50.8 | Other severe and complicated Plasmodium falciparum malaria | |
| blackwater | B50.8 | Other severe and complicated Plasmodium falciparum malaria | |
| blister | B00.1 | Herpesviral vesicular dermatitis | |
| Bolivian hemorrhagic | A96.1 | Machupo hemorrhagic fever | |
| Bonvale dam | T73.3 | Exhaustion due to excessive exertion | not billable |
| boutonneuse | A77.1 | Spotted fever due to Rickettsia conorii | |
| Brazilian purpuric | A48.4 | Brazilian purpuric fever | |
| breakbone | A90 | Dengue fever [classical dengue] | |
| Bullis | A77.0 | Spotted fever due to Rickettsia rickettsii | |
| Bunyamwera | A92.8 | Other specified mosquito-borne viral fevers | |
| Burdwan | B55.0 | Visceral leishmaniasis | |
| Bwamba | A92.8 | Other specified mosquito-borne viral fevers | |
| Canton | A75.9 | Typhus fever, unspecified | |
| catarrhal | J00 | Acute nasopharyngitis [common cold] | |
| cat-scratch | A28.1 | Cat-scratch disease | |
| Central Asian hemorrhagic | A98.0 | Crimean-Congo hemorrhagic fever | |
| cerebrospinal meningococcal | A39.0 | Meningococcal meningitis | |
| Chagres | B50.9 | Plasmodium falciparum malaria, unspecified | |
| Chandipura | A92.8 | Other specified mosquito-borne viral fevers | |
| Changuinola | A93.1 | Sandfly fever | |
| Chikungunya | A92.0 | Chikungunya virus disease | |
| Chitral | A93.1 | Sandfly fever | |
| Colorado tick | A93.2 | Colorado tick fever | |
| Congo virus | A98.0 | Crimean-Congo hemorrhagic fever | |
| continued malarial | B50.9 | Plasmodium falciparum malaria, unspecified | |
| Crimean-Congo hemorrhagic | A98.0 | Crimean-Congo hemorrhagic fever | |
| dandy | A90 | Dengue fever [classical dengue] | |
| dengue | A90 | Dengue fever [classical dengue] | |
| desert | B38.0 | Acute pulmonary coccidioidomycosis | |
| drug induced | R50.2 | Drug induced fever | |
| enteric | A01.00 | Typhoid fever, unspecified | |
| enteroviral exanthematous | A88.0 | Enteroviral exanthematous fever [Boston exanthem] | |
| ephemeral | R50.9 | Fever, unspecified | |
| epidemic hemorrhagic | A98.5 | Hemorrhagic fever with renal syndrome | |
| estivo-autumnal | B50.9 | Plasmodium falciparum malaria, unspecified | |
| famine | A75.0 | Epidemic louse-borne typhus fever due to Rickettsia prowazekii | |
| five day | A79.0 | Trench fever | |
| following delivery | O86.4 | Pyrexia of unknown origin following delivery | |
| Fort Bragg | A27.89 | Other forms of leptospirosis | |
| gastroenteric | A01.00 | Typhoid fever, unspecified | |
| Guama | A92.8 | Other specified mosquito-borne viral fevers | |
| Haverhill | A25.1 | Streptobacillosis | |
| hay | J30.1 | Allergic rhinitis due to pollen | |
| heat | T67.01 | Heatstroke and sunstroke | not billable |
| hematuric, bilious | B50.8 | Other severe and complicated Plasmodium falciparum malaria | |
| hemoglobinuric | B50.8 | Other severe and complicated Plasmodium falciparum malaria | |
| hemorrhagicNOS | A94 | Unspecified arthropod-borne viral fever | |
| icterohemorrhagic | A27.0 | Leptospirosis icterohemorrhagica | |
| Indiana | A93.8 | Other specified arthropod-borne viral fevers | |
| infective | B99.9 | Unspecified infectious disease | |
| iodide | R50.2 | Drug induced fever | |
| Japanese river | A75.3 | Typhus fever due to Rickettsia tsutsugamushi | |
| Juninhemorrhagic | A96.0 | Junin hemorrhagic fever | |
| Katayama | B65.2 | Schistosomiasis due to Schistosoma japonicum | |
| kedani | A75.3 | Typhus fever due to Rickettsia tsutsugamushi | |
| Kenya | A77.1 | Spotted fever due to Rickettsia conorii | |
| Kew Garden | A79.1 | Rickettsialpox due to Rickettsia akari | |
| Korean hemorrhagic | A98.5 | Hemorrhagic fever with renal syndrome | |
| Lassa | A96.2 | Lassa fever | |
| Lone Star | A77.0 | Spotted fever due to Rickettsia rickettsii | |
| Machupohemorrhagic | A96.1 | Machupo hemorrhagic fever | |
| Malta | A23.9 | Brucellosis, unspecified | |
| Marseilles | A77.1 | Spotted fever due to Rickettsia conorii | |
| Mayaro | A92.8 | Other specified mosquito-borne viral fevers | |
| Mediterranean | A23.9 | Brucellosis, unspecified | |
| Meuse | A79.0 | Trench fever | |
| Mexican | A75.2 | Typhus fever due to Rickettsia typhi | |
| mianeh | A68.1 | Tick-borne relapsing fever | |
| mosquito-borne | A92.9 | Mosquito-borne viral fever, unspecified | |
| Mucambo | A92.8 | Other specified mosquito-borne viral fevers | |
| mud | A27.9 | Leptospirosis, unspecified | |
| neutropenic | D70.9 | Neutropenia, unspecified | |
| newborn | P81.9 | Disturbance of temperature regulation of newborn, unspecified | |
| Nine-Mile | A78 | Q fever | |
| non-exanthematous tick | A93.2 | Colorado tick fever | |
| North Asian tick-borne | A77.2 | Spotted fever due to Rickettsia siberica | |
| Omsk hemorrhagic | A98.1 | Omsk hemorrhagic fever | |
| O'nyong-nyong | A92.1 | O'nyong-nyong fever | |
| Oropouche | A93.0 | Oropouche virus disease | |
| Oroya | A44.0 | Systemic bartonellosis | |
| pacific coast tick | A77.8 | Other spotted fevers | |
| Panama | B50.9 | Plasmodium falciparum malaria, unspecified | |
| Pappataci | A93.1 | Sandfly fever | |
| paratyphoid | A01.4 | Paratyphoid fever, unspecified | |
| parrot | A70 | Chlamydia psittaci infections | |
| periodic | M04.1 | Periodic fever syndromes | |
| persistent | R50.9 | Fever, unspecified | |
| petechial | A39.0 | Meningococcal meningitis | |
| pharyngoconjunctival | B30.2 | Viral pharyngoconjunctivitis | |
| Philippine hemorrhagic | A91 | Dengue hemorrhagic fever | |
| phlebotomus | A93.1 | Sandfly fever | |
| Piry | A93.8 | Other specified arthropod-borne viral fevers | |
| Pixuna | A92.8 | Other specified mosquito-borne viral fevers | |
| Plasmodium ovale | B53.0 | Plasmodium ovale malaria | |
| polioviral | A80.4 | Acute nonparalytic poliomyelitis | |
| Pontiac | A48.2 | Nonpneumonic Legionnaires' disease [Pontiac fever] | |
| postimmunization | R50.83 | Postvaccination fever | |
| postoperative | R50.82 | Postprocedural fever | |
| posttransfusion | R50.84 | Febrile nonhemolytic transfusion reaction | |
| postvaccination | R50.83 | Postvaccination fever | |
| presenting with conditions classified elsewhere | R50.81 | Fever presenting with conditions classified elsewhere | |
| pretibial | A27.89 | Other forms of leptospirosis | |
| puerperal | O86.4 | Pyrexia of unknown origin following delivery | |
| Q | A78 | Q fever | |
| quadrilateral | A78 | Q fever | |
| quartan | B52.9 | Plasmodium malariae malaria without complication | |
| Queensland | A77.3 | Spotted fever due to Rickettsia australis | |
| quintan | A79.0 | Trench fever |
Index terms and codes are reproduced from the official ICD-10-CM FY2027 release. The Alphabetic Index is a finding aid — a code must always be verified in the Tabular List before it is reported. Data sources