2026 ICD-10-CM Diagnosis Code A98.1Omsk hemorrhagic fever

ICD-10-CM Codes›A00–B99›A90-A99›A98

ICD-10-CM A98.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A98.1 is a billable ICD-10-CM diagnosis code for Omsk hemorrhagic 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
A98.1
Billable Status
Yes — Valid for Submission
Code Describes
Omsk hemorrhagic fever
Short Description
Omsk hemorrhagic fever
Same as the full description in the CMS dataset.
Parent Code
A98
Other viral hemorrhagic fevers, not elsewhere classified

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA90-A99Arthropod-borne viral fevers and viral hemorrhagic fevers
CategoryA98Other viral hemorrhagic fevers, not elsewhere classified
This CodeA98.1Omsk hemorrhagic fever

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Omsk hemorrhagic fever

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.

    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • hemorrhagic (arthropod-borne) NOS
        • Omsk
    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • Omsk hemorrhagic
    • Omsk hemorrhagic fever

Clinical ClassificationClinical

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

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

Patient EducationClinical

Hemorrhagic Fevers

Viral hemorrhagic fevers (VHFs) are a group of illnesses caused by four families of viruses. These include the Ebola and Marburg, Lassa fever, and yellow fever viruses. VHFs have common features: they affect many organs, they damage the blood vessels, and they affect the body's ability to regulate itself.

Read the full article at MedlinePlus

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

Convert A98.1 to ICD-9-CMHistory

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

ICD-9-CM
065.1 Omsk hemorrhagic fever
Exact Match The mapping is direct, with no qualifiers.

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 A98.1Overview

Is A98.1 (Other viral hemorrhagic fevers, not elsewhere classified) a billable code?

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

What MS-DRG does A98.1 group to?

When Omsk hemorrhagic 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 A98.1?

Under the General Equivalence Mappings, Omsk hemorrhagic fever converts to ICD-9-CM 065.1 (Omsk hemorrhagic fever). The mapping is a direct match.

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.