2026 ICD-10-CM Diagnosis Code B27.09Gammaherpesviral mononucleosis with other complications
ICD-10-CM Codes›A00–B99›B25-B34›B27
- Billable — Valid for Submission
- Not Chronic
B27.09 is a billable ICD-10-CM diagnosis code for gammaherpesviral mononucleosis with other complications. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Viral infection.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Diffuse large B-cell lymphoma co-occurrent with chronic inflammation caused by Epstein-Barr virus
- Epstein Barr virus infection of the central nervous system
- Epstein-Barr dacryoadenitis
- Epstein-Barr virus associated gastric carcinoma
- Epstein-Barr virus encephalitis
- Epstein-Barr virus infection of the retina
- Epstein-Barr virus infectious mononucleosis
- Infection of lacrimal gland caused by virus
- Mucocutaneous ulcer caused by Epstein-Barr virus
- Myelitis caused by Epstein-Barr virus
- Myelitis caused by Human herpes virus
- Neoplastic sequelae of disorders
- Primary carcinoma of stomach due to Epstein-Barr virus disease
- Viral pneumonia due to Epstein-Barr virus infectious mononucleosis
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Hepatomegaly in gammaherpesviral mononucleosis
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Adenitis - See Also: Lymphadenitis;
- epidemic, acute - B27.09
- infectious (acute) (epidemic) - B27.09
- Hepatomegaly - See Also: Hypertrophy, liver;
- Mononucleosis, infectious - B27.90
- Epstein-Barr (virus) - B27.00
- with
- complication NEC - B27.09
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Adenitis
- epidemic, acute
- Adenitis
- infectious (acute) (epidemic)
- Hepatomegaly
- in mononucleosis
- gammaherpesviral
- Mononucleosis, infectious
- Epstein-Barr (virus)
- with
- complication NEC
- Mononucleosis, infectious
- gammaherpesviral
- with
- complication NEC
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Infectious Mononucleosis
Infectious mononucleosis (mono) is a disease caused by viruses.The most common cause is the Epstein-Barr virus (EBV). Mono is contagious, which means it can spread from person to person. It is common among teenagers and young adults, especially college students.
The full article covers:
- What is infectious mononucleosis (mono)?
- What causes infectious mononucleosis (mono)?
- What are the symptoms of infectious mononucleosis (mono)?
- How is infectious mononucleosis (mono) diagnosed?
- What are the treatments for infectious mononucleosis (mono)?
- Can infectious mononucleosis (mono) be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert B27.09 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About B27.09Overview
Is B27.09 (Gammaherpesviral mononucleosis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report gammaherpesviral mononucleosis with other complications on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does B27.09 group to?
When gammaherpesviral mononucleosis with other complications 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 B27.09?
Under the General Equivalence Mappings, gammaherpesviral mononucleosis with other complications converts to ICD-9-CM 075 (infectious mononucleosis). 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.
