2027 ICD-10-CM Diagnosis Code B40Blastomycosis

ICD-10-CM Codes›A00–B99›B35-B49›B40

ICD-10-CM B40
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

B40 is a non-billable ICD-10-CM category code for blastomycosis, so it cannot be submitted on claims. Use a more specific code from this category instead, such as B40.0, B40.1, B40.2, and B40.3.

Code Identity

ICD-10-CM Code
B40
Billable Status
No — Non-Billable Category
Code Describes
Blastomycosis
Short Description
Blastomycosis
Same as the full description in the CMS dataset.
Chapter
B35-B49
Mycoses

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB35-B49Mycoses
CategoryB40Blastomycosis
This CodeB40Blastomycosis

Specific Coding for BlastomycosisOverview

Non-specific codes like B40 require more characters. Use one of these billable codes instead:

  • Use B40.0 for Acute pulmonary blastomycosis

  • Use B40.1 for Chronic pulmonary blastomycosis

  • Use B40.2 for Pulmonary blastomycosis, unspecified

  • Use B40.3 for Cutaneous blastomycosis

  • Use B40.7 for Disseminated blastomycosis

  • B40.8 for Other forms of blastomycosis

  • Use B40.81 for Blastomycotic meningoencephalitis

  • Use B40.89 for Other forms of blastomycosis

  • Use B40.9 for Blastomycosis, unspecified

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to B40: its own notes plus those printed at block B35-B49 and Chapter 1. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • diseases generally recognized as communicable or transmissible

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

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

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block B35-B49 Mycoses applies to 104 codes
  • hypersensitivity pneumonitis due to organic dust (J67.-)
  • mycosis fungoides (C84.0-)
From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • carrier or suspected carrier of infectious disease (Z22.-)
  • certain localized infections - see body system-related chapters
  • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
  • infectious and parasitic diseases specific to the perinatal period (P35-P39)
  • influenza and other acute respiratory infections (J00-J22)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • code to identify resistance to antimicrobial drugs (Z16.-)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Clinical InformationClinical

  • Blastomycosis

    a fungal infection by blastomyces that may appear in two forms: 1, a primary lesion characterized by the formation of a small cutaneous nodule and small nodules along the lymphatics that may heal within several months; and 2, chronic granulomatous lesions characterized by thick crusts, warty growths, and unusual vascularity and infection in the middle or upper lobes of the lung.

Patient EducationClinical

Fungal Infections

If you have ever had athlete's foot or a yeast infection, you can blame a fungus. A fungus is a primitive organism. Mushrooms, mold and mildew are examples. Fungi live in air, in soil, on plants and in water. Some live in the human body. Only about half of all types of fungi are harmful.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About B40Overview

What is the ICD-10 code for blastomycosis?

B40 is the ICD-10-CM category for blastomycosis, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is B40 (Blastomycosis) a billable code?

No. This is a category header that groups the codes for blastomycosis, and headers cannot be submitted on claims. Claims for blastomycosis need a more specific code from this category, such as B40.0, B40.1, and B40.2.

Can B40 be reported with a code from B41?

Not as a rule. The Excludes1 note on B40 lists "Brazilian blastomycosis (B41.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).