B27 ICD-10-CA category: Infectious mononucleosis
B27 isn’t a code on its own. Choose one of the 4 codes beneath it, the one the documentation supports.
Official description
B27Infectious mononucleosis
ICD-10-CA · Canada
Codes in B27
B27 isn’t a code on its own. Open the code that matches what the note documents.
Notes for B27
As CIHI prints them, with any note B27 takes from the headings above it.
Includes
- Glandular fevermonocytic anginaPfeiffer's disease
- Diseases generally recognized as communicable or transmissibleFrom Chapter 1: Certain infectious and parasitic diseases (A00-B99)
Use additional code
Add a code for this detail when the note documents it.
- Use additional code (U82-U84) to identify resistance to antimicrobial drugsFrom Chapter 1: Certain infectious and parasitic diseases (A00-B99)
Excludes
Conditions classified elsewhere.
- Carrier or suspected carrier of infectious disease (Z22.-)certain localized infections - see body system-related chaptersinfectious and parasitic diseases:• complicating pregnancy, childbirth and the puerperium [except obstetrical tetanus] (O98.-)• specific to the perinatal period [except tetanus neonatorum, whooping cough, congenital syphilis, perinatal gonococcal infection and perinatal human immunodeficiency virus [HIV] disease] (P35-P39)influenza and other acute respiratory infections (J00-J22)From Chapter 1: Certain infectious and parasitic diseases (A00-B99)
Where B27 sits
- 1ChapterChapter 1: Certain infectious and parasitic diseases (A00-B99)
- 2Block B25-B34Other viral diseases
- 3Category B27Infectious mononucleosis
Source and release
- Data release
- ICD-10-CA · FY 2026–2027
- Effective date
- Apr 1, 2026
- Publisher
- CIHI
This page is built from the ICD-10-CA catalog that Vero Codes reads when it suggests codes: Canadian Institute for Health Information’s FY 2026–2027 release, imported from the publisher’s file and checked against it. The description, notes and structured data come from the same record.
Frequently asked questions
Is B27 a valid ICD-10-CA code?
No. B27 (Infectious mononucleosis) is a category heading in CIHI’s ICD-10-CA FY 2026–2027 release. It holds 4 codes; record the one the documentation supports.
Where is B27 in ICD-10-CA?
B27 sits under B25-B34 Other viral diseases, within Chapter 1: Certain infectious and parasitic diseases (A00-B99).
What coding notes apply to B27?
ICD-10-CA lists Includes, Use additional code, Excludes notes for B27, including those from the headings it sits under. They are listed on this page with where each one comes from.
Which ICD-10-CA release does this page use?
It uses CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026 to Mar 31, 2027. It is a reference: confirm the code against the current list and the payer’s rules before you submit it.