2026 ICD-10-CM Diagnosis Code A28.9Zoonotic bacterial disease, unspecified

ICD-10-CM Codes›A00–B99›A20-A28›A28

ICD-10-CM A28.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A28.9 is a billable ICD-10-CM diagnosis code for zoonotic bacterial disease, 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections.

Code Identity

ICD-10-CM Code
A28.9
Billable Status
Yes — Valid for Submission
Code Describes
Zoonotic bacterial disease, unspecified
Short Description
Zoonotic bacterial disease, unspecified
Same as the full description in the CMS dataset.
Parent Code
A28
Other zoonotic bacterial diseases, not elsewhere classified

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA20-A28Certain zoonotic bacterial diseases
CategoryA28Other zoonotic bacterial diseases, not elsewhere classified
This CodeA28.9Zoonotic bacterial disease, unspecified

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.

    • Disease, diseased
      • bacterial
        • zoonotic
    • Disease, diseased
      • zoonotic, bacterial
    • Infection, infected, infective(opportunistic)
      • zoonotic bacterial NOS
    • Vibriosis

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

Bacterial Infections

Bacteria are tiny organisms (living things) that have only one cell. Under a microscope, they look like balls, rods, or spirals. They can be found almost everywhere on Earth. There are lots of bacteria in and on your body. In fact, your body has about 10 times more bacteria cells than human cells.

The full article covers:

  • What are bacteria?
  • How do bacterial infections spread?
  • What are the treatments for bacterial infections?
  • Can bacterial infections be prevented?

Read the full article at MedlinePlus

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

Convert A28.9 to ICD-9-CMHistory

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

ICD-9-CM
027.9 Zoonotic bact dis 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 A28.9Overview

Is A28.9 (Other zoonotic bacterial diseases, not elsewhere classified) a billable code?

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

What MS-DRG does A28.9 group to?

When zoonotic bacterial disease, 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 A28.9?

Under the General Equivalence Mappings, zoonotic bacterial disease, unspecified converts to ICD-9-CM 027.9 (zoonotic bact dis 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.