2026 ICD-10-CM Diagnosis Code B08.09Other orthopoxvirus infections

ICD-10-CM Codes›A00–B99›B00-B09›B08

ICD-10-CM B08.09
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B08.09 is a billable ICD-10-CM diagnosis code for other orthopoxvirus infections. 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. Coders also document this condition as disease caused by Orthopoxvirus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Viral infection.

Code Identity

ICD-10-CM Code
B08.09
Billable Status
Yes — Valid for Submission
Code Describes
Other orthopoxvirus infections
Short Description
Other orthopoxvirus infections
Same as the full description in the CMS dataset.
Parent Code
B08.0
Other orthopoxvirus infections

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB00-B09Viral infections characterized by skin and mucous membrane lesions
CategoryB08Other viral infections characterized by skin and mucous membrane lesions, not elsewhere classified
This CodeB08.09Other orthopoxvirus infections

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Disease caused by Orthopoxvirus
  • Orthopoxvirus encephalitis

Tabular List NotesGuidance

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

Inclusion Terms

  • Orthopoxvirus infection NOS

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.

    • Infection, infected, infective(opportunistic)
      • orthopoxvirus NEC
    • Orthopoxvirus

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

Viral Infections

Viruses are very tiny germs. They are made of genetic material (either DNA or RNA) inside of a protein coating. There are a huge number of viruses on earth. Only a small number of them can infect humans. Those viruses can infect our cells, which may cause disease.

The full article covers:

  • What are viruses?
  • How are viruses spread?
  • How do viruses cause disease?
  • What are the treatments for viral infections?
  • Can viral infections be prevented?

Read the full article at MedlinePlus

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

Convert B08.09 to ICD-9-CMHistory

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

ICD-9-CM
059.00 Orthopoxvirus infect NOS
Approximate The match is approximate rather than exact.
ICD-9-CM
059.09 Orthopoxvirus infect NEC
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 B08.09Overview

Is B08.09 (Other orthopoxvirus infections) a billable code?

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

What MS-DRG does B08.09 group to?

When other orthopoxvirus infections 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 B08.09?

Under the General Equivalence Mappings, other orthopoxvirus infections converts to ICD-9-CM 059.00 (orthopoxvirus infect NOS) and 059.09 (orthopoxvirus infect NEC). 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.