ICD-10-CM 2027 diagnosis code

B40Blastomycosis

Not billable — use a more specific code

B40 is a header code, so it can't be reported by itself. Choose one of the 7 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About B40

B40 is the ICD-10-CM diagnosis code for blastomycosis. It belongs to block B35-B49 (mycoses) and chapter 1 (certain infectious and parasitic diseases). It is a header code, so it can't be reported by itself; one of its 7 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: B40.0 (blastomycosis), B40.1 (blastomycosis), B40.2 (unspecified), B40.3 (blastomycosis), B40.7 (blastomycosis), B40.8 (blastomycosis) and B40.9 (unspecified).

Don't report B40 together with the conditions in its Excludes1 note: Brazilian blastomycosis (B41.-) and keloidal blastomycosis (B48.0).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under B40

Coding notes

Excludes1Not coded here — never report together with this code

Brazilian blastomycosis (B41.-)
keloidal blastomycosis (B48.0)

Notes that apply from higher levels

Instructions written at a parent level also apply to B40.

Broader instructions also apply from B35-B49 Mycoses and Chapter 1: Certain infectious and parasitic diseases.

Code history

2016
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2021
2022
2023
2024
2025
2026
2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about B40

Is B40 billable?: No. B40 is a header code. Report one of its more specific subcodes instead.