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B04 ICD-10-CA code: Mpox [monkeypox]

B04 is the ICD-10-CA code for “Mpox [monkeypox]” in CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026.

Official description

B04

Mpox [monkeypox]

ICD-10-CA · Canada

Index terms

Entries in CIHI’s alphabetical index that lead to B04. Searching the index by the condition the note names is how coders reach this code.

  • Monkeypox

Notes for B04

As CIHI prints them, with any note B04 takes from the headings above it.

Includes

  • 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)

Note

  • The updated ICD-10-CA code is B04 Mpox [monkeypox]. There is no change to the classification of mpox. It is still classified to B04 Mpox [monkeypox] per previous direction.

Where B04 sits

  1. 1ChapterChapter 1: Certain infectious and parasitic diseases (A00-B99)
  2. 2Block B00-B09Viral infections characterized by skin and mucous membrane lesions
  3. 3Valid code B04Mpox [monkeypox]

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.

See B04 in the CIHI source

Frequently asked questions

What does ICD-10-CA code B04 mean?

B04 is the ICD-10-CA code for “Mpox [monkeypox]” in CIHI’s ICD-10-CA FY 2026–2027 release.

Where is B04 in ICD-10-CA?

B04 sits under B00-B09 Viral infections characterized by skin and mucous membrane lesions, within Chapter 1: Certain infectious and parasitic diseases (A00-B99).

What coding notes apply to B04?

ICD-10-CA lists Note, Includes, Use additional code, Excludes notes for B04, 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.

Codes beside B04

B00Herpesviral [herpes simplex] infectionsB01Varicella [chickenpox]B02Zoster [herpes zoster]B03SmallpoxB05MeaslesB06Rubella [German measles]B07Viral wartsB08Other viral infections characterized by skin and mucous membrane lesions, not elsewhere classifiedB09Unspecified viral infection characterized by skin and mucous membrane lesions