2026 ICD-10-CM Diagnosis Code A25.9Rat-bite fever, unspecified

ICD-10-CM Codes›A00–B99›A20-A28›A25

ICD-10-CM A25.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A25.9 is a billable ICD-10-CM diagnosis code for rat-bite fever, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 867 through 869. Coders also document this condition as rat bite fever. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections.

Code Identity

ICD-10-CM Code
A25.9
Billable Status
Yes — Valid for Submission
Code Describes
Rat-bite fever, unspecified
Short Description
Rat-bite fever, unspecified
Same as the full description in the CMS dataset.
Parent Code
A25
Rat-bite fevers

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA20-A28Certain zoonotic bacterial diseases
CategoryA25Rat-bite fevers
This CodeA25.9Rat-bite fever, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Rat bite 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)
      • rat-bite
    • Rat-bite fever

Clinical ClassificationClinical

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

CCSR INF003
Bacterial infections
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Animal Bites

Wild animals usually avoid people. They might attack, however, if they feel threatened, are sick, or are protecting their young or territory. Attacks by pets are more common. Animal bites rarely are life-threatening, but if they become infected, you can develop serious medical problems.

Read the full article at MedlinePlus

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

Convert A25.9 to ICD-9-CMHistory

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

ICD-9-CM
026.9 Rat-bite fever NOS
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 A25.9Overview

Is A25.9 (Rat-bite fevers) a billable code?

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

What MS-DRG does A25.9 group to?

When rat-bite fever, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 867, 868, 869, with relative weights from 0.7297 to 2.0932 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of A25.9?

Under the General Equivalence Mappings, rat-bite fever, unspecified converts to ICD-9-CM 026.9 (rat-bite fever NOS). 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.