2026 ICD-10-CM Diagnosis Code B25.9Cytomegaloviral disease, unspecified

ICD-10-CM Codes›A00–B99›B25-B34›B25

ICD-10-CM B25.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B25.9 is a billable ICD-10-CM diagnosis code for cytomegaloviral disease, unspecified. 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, 974 through 976. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Viral infection.

Code Identity

ICD-10-CM Code
B25.9
Billable Status
Yes — Valid for Submission
Code Describes
Cytomegaloviral disease, unspecified
Short Description
Cytomegaloviral disease, unspecified
Same as the full description in the CMS dataset.
Parent Code
B25
Cytomegaloviral disease

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB25-B34Other viral diseases
CategoryB25Cytomegaloviral disease
This CodeB25.9Cytomegaloviral disease, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cytomegalovirus infection
  • Cytomegalovirus infection of skin
  • Cytomegalovirus viremia
  • Disseminated cytomegalovirus infection
  • Infection caused by Cytomegalovirus co-occurrent with human immunodeficiency virus infection
  • Infection of central nervous system caused by Cytomegalovirus
  • Myelitis caused by Cytomegalovirus
  • Myelitis caused by Human herpes virus
  • Ulcer of skin caused by Cytomegalovirus
  • Ulcerative cytomegalovirus lesion
  • Viremia

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.

    • Cytomegalovirus infection
    • Disease, diseased
      • cytomegalic inclusion (generalized)
    • Disease, diseased
      • cytomegaloviral
    • Disease, diseased
      • inclusion
    • Disease, diseased
      • inclusion
        • salivary gland
    • Disease, diseased
      • salivary gland or duct
        • inclusion
    • Disease, diseased
      • salivary gland or duct
        • virus
    • Infection, infected, infective(opportunistic)
      • cytomegalovirus, cytomegaloviral
    • Virus, viral
      • cytomegalovirus

Clinical ClassificationClinical

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

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

Clinical InformationClinical

  • Viremia

    the presence of viruses in the blood.

  • Adenovirus DNA Viremia|AdV DNA Viremia

    a laboratory test result indicating the presence of adenovirus dna in the blood.

  • Grade 2 Viremia, CTCAE|Grade 2 Viremia

    moderate symptoms; medical intervention indicated

  • Grade 3 Viremia, CTCAE|Grade 3 Viremia

    severe or medically significant but not immediately life-threatening; hospitalization or prolongation of existing hospitalization indicated

  • Viremia

    a laboratory test result indicating the presence of a virus in the blood.

  • Viremia, CTCAE|Viremia

    a disorder characterized by the presence of a virus in the blood stream.

Patient EducationClinical

Cytomegalovirus Infections

Cytomegalovirus (CMV) is a virus found around the world. It is related to the viruses that cause chickenpox and infectious mononucleosis (mono). Between 50% and 80% of adults in the United States have had a CMV infection by age 40. Once CMV is in a person's body, it stays there for life.

Read the full article at MedlinePlus

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

Convert B25.9 to ICD-9-CMHistory

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

ICD-9-CM
078.5 Cytomegaloviral disease
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 B25.9Overview

Is B25.9 (Cytomegaloviral disease) a billable code?

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

What MS-DRG does B25.9 group to?

When cytomegaloviral disease, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 865, 866, 974, 975, 976, with relative weights from 0.8696 to 2.8860 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of B25.9?

Under the General Equivalence Mappings, cytomegaloviral disease, unspecified converts to ICD-9-CM 078.5 (cytomegaloviral disease). 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.