2026 ICD-10-CM Diagnosis Code A77.49Other ehrlichiosis

ICD-10-CM Codes›A00–B99›A75-A79›A77

ICD-10-CM A77.49
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

A77.49 is a billable ICD-10-CM diagnosis code for other ehrlichiosis. 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 anaplasmosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Parasitic, other specified and unspecified infections.

Code Identity

ICD-10-CM Code
A77.49
Billable Status
Yes — Valid for Submission
Code Describes
Other ehrlichiosis
Short Description
Other ehrlichiosis
Same as the full description in the CMS dataset.
Parent Code
A77.4
Ehrlichiosis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionA75-A79Rickettsioses
CategoryA77Spotted fever [tick-borne rickettsioses]
This CodeA77.49Other ehrlichiosis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Anaplasmosis
  • Human anaplasmosis caused by Anaplasma phagocytophilum
  • Human ehrlichiosis
  • Human ehrlichiosis caused by Ehrlichia ewingii

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Ehrlichiosis due to E. ewingii
  • Ehrlichiosis due to E. muris euclairensis

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.

    • Anaplasmosis [A. phagocytophilum](transfusion transmitted)
      • human
    • Ehrlichiosis
      • due to
        • E. ewingii
    • Ehrlichiosis
      • due to
        • E. muris euclairensis
    • Ehrlichiosis
      • due to
        • specified organism NEC
    • Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
      • spotted
        • Ehrlichiosis
          • due to
            • specified organism NEC

Clinical ClassificationClinical

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

CCSR INF009
Parasitic, other specified and unspecified infections
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Ehrlichiosis

    a tick-borne disease characterized by fever; headache; myalgias; anorexia; and occasionally rash. it is caused by several bacterial species and can produce disease in dogs; cattle; sheep; goats; horses; and humans. the primary species causing human disease are ehrlichia chaffeensis; anaplasma phagocytophilum; and ehrlichia ewingii.

  • Anaplasmosis

    a disease usually in cattle caused by parasitization of the red blood cells by bacteria of the genus anaplasma.

  • Anaplasma

    a genus of gram-negative bacteria whose organisms are obligate parasites of vertebrates. species are transmitted by arthropod vectors with the host range limited to ruminants. anaplasma marginale is the most pathogenic species and is the causative agent of severe bovine anaplasmosis.

  • Anaplasmosis

    an infection that is caused by anaplasma phagocytophilum, which is transmitted to humans by infected ticks; it is characterized by fever, headache, chills, and myalgia.

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 A77.49 to ICD-9-CMHistory

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

ICD-9-CM
082.49 Ehrlichiosis NEC
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 A77.49Overview

Is A77.49 (Ehrlichiosis) a billable code?

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

What MS-DRG does A77.49 group to?

When other ehrlichiosis 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 A77.49?

Under the General Equivalence Mappings, other ehrlichiosis converts to ICD-9-CM 082.49 (ehrlichiosis NEC). 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.