2026 ICD-10-CM Diagnosis Code A93.2Colorado tick fever

ICD-10-CM Codes›A00–B99›A90-A99›A93

ICD-10-CM A93.2
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A93.2 is a billable ICD-10-CM diagnosis code for Colorado tick fever. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 865 through 866. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Viral infection.

Code Identity

ICD-10-CM Code
A93.2
Billable Status
Yes — Valid for Submission
Code Describes
Colorado tick fever
Short Description
Colorado tick fever
Same as the full description in the CMS dataset.
Parent Code
A93
Other arthropod-borne viral fevers, not elsewhere classified

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA90-A99Arthropod-borne viral fevers and viral hemorrhagic fevers
CategoryA93Other arthropod-borne viral fevers, not elsewhere classified
This CodeA93.2Colorado tick fever

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Colorado tick fever
  • Infection caused by Coltavirus

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • American
      • mountain tick fever
    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • American
        • mountain (tick)
    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • Colorado tick (virus)
    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • mountain
        • tick (American) (Colorado) (viral)
    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • non-exanthematous tick
    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • tick
        • American mountain
    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • tick
        • Colorado
    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • tick
        • mountain
    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • tick
        • nonexanthematous
    • Mountain
      • tick fever
    • Nonexanthematous tick fever

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INF008
Viral infection
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Colorado Tick Fever

    a febrile illness characterized by chills, aches, vomiting, leukopenia, and sometimes encephalitis. it is caused by the colorado tick fever virus, a reovirus transmitted by the tick dermacentor andersoni.

  • Colorado tick fever virus

    a species of coltivirus transmitted by the tick dermacentor andersonii and causing fever, chills, aching head and limbs, and often vomiting. it occurs in the northwestern united states, except the pacific coast.

Patient EducationClinical

Tick Bites

Ticks are small parasites. They may look like insects, but they have eight legs and are related to spiders. Ticks feed on the blood of people and warm-blooded animals. There are many types of ticks in the United States, and they live in different parts of the country.

The full article covers:

  • What are ticks?
  • Why do I need to be worried about tick bites?
  • What happens if I get bitten by a tick?
  • How do I remove a tick?
  • When do I need to contact my health care provider about a tick bite?
  • How can I prevent tick bites?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert A93.2 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
066.1 Tick-borne fever
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About A93.2Overview

Is A93.2 (Other arthropod-borne viral fevers, not elsewhere classified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report Colorado tick fever on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does A93.2 group to?

When Colorado tick fever is the principal diagnosis on an inpatient stay, it groups to MS-DRG 865, 866, with relative weights from 0.8696 to 1.4983 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of A93.2?

Under the General Equivalence Mappings, Colorado tick fever converts to ICD-9-CM 066.1 (tick-borne fever). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.