Infectious mononucleosis (B27) ICD-10-CM
The B27 code range covers infectious mononucleosis with 21 ICD-10-CM diagnosis codes. 16 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Includes
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
- glandular fever
- monocytic angina
- Pfeiffer's disease
Codes in the B27 Range 21 codes · 16 billable
- B27 Infectious mononucleosisNon-billable
- B27.0 Gammaherpesviral mononucleosisNon-billable
- B27.00 Gammaherpesviral mononucleosis without complication
- B27.01 Gammaherpesviral mononucleosis with polyneuropathy
- B27.02 Gammaherpesviral mononucleosis with meningitis
- B27.09 Gammaherpesviral mononucleosis with other complications
- B27.1 Cytomegaloviral mononucleosisNon-billable
- B27.10 Cytomegaloviral mononucleosis without complications
- B27.11 Cytomegaloviral mononucleosis with polyneuropathy
- B27.12 Cytomegaloviral mononucleosis with meningitis
- B27.19 Cytomegaloviral mononucleosis with other complication
- B27.8 Other infectious mononucleosisNon-billable
- B27.80 Other infectious mononucleosis without complication
- B27.81 Other infectious mononucleosis with polyneuropathy
- B27.82 Other infectious mononucleosis with meningitis
- B27.89 Other infectious mononucleosis with other complication
- B27.9 Infectious mononucleosis, unspecifiedNon-billable
- B27.90 Infectious mononucleosis, unspecified without complication
- B27.91 Infectious mononucleosis, unspecified with polyneuropathy
- B27.92 Infectious mononucleosis, unspecified with meningitis
- B27.99 Infectious mononucleosis, unspecified with other complication
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the B27 range.
Infectious Mononucleosis
A common, acute infection usually caused by the Epstein-Barr virus (HERPESVIRUS 4, HUMAN). There is an increase in mononuclear white blood cells and other atypical lymphocytes, generalized lymphadenopathy, splenomegaly, and occasionally hepatomegaly with hepatitis.
About the B27 Code Range
Infectious mononucleosis is an acute infection usually caused by the Epstein-Barr virus.
The codes first separate gammaherpesviral mononucleosis (B27.0) from cytomegaloviral mononucleosis (B27.1), other infectious mononucleosis (B27.8), and unspecified infectious mononucleosis (B27.9). Each group then separates cases without complications from cases with polyneuropathy, meningitis, or another complication.
Questions About This Page
How many billable codes are in the B27 range?
Of the 21 codes in this range, 16 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the B27 range classify?
The range classifies infectious mononucleosis. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
