2026 ICD-10-CM Diagnosis Code B40Blastomycosis

ICD-10-CM Codes›A00–B99›B35-B49›B40

ICD-10-CM B40
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

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
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

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Type 1 Excludes

  • Brazilian blastomycosis B41
  • keloidal blastomycosis B48.0

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.

  • Lobomycosis

    a chronic, fungal, subcutaneous infection endemic in rural regions in south america and central america. the causal organism is lacazia labol.

  • Paracoccidioidomycosis

    a mycosis affecting the skin, mucous membranes, lymph nodes, and internal organs. it is caused most often by paracoccidioides brasiliensis. it is also called paracoccidioidal granuloma.

  • Blastomyces

    a genus of onygenacetous mitosporic fungi whose perfect state is ajellomyces (see onygenales). the species blastomyces dermatitidis (perfect state is ajellomyces dermatitidis) causes blastomycosis.

  • Blastomycosis

    a fungal infection caused by inhalation of spores of blastomyces dermatitidis. it presents with flu-like symptoms including fever, chills, cough, pleuritic chest pain and myalgias. it may lead to a chronic granulomatous pulmonary infection and disseminate to other anatomic sites including skin, nervous system and bones.

  • North American Blastomycosis|Blastomyces Dermatitidis Infection

    a pulmonary disease resulting from infection with blastomyces dermatitidis, which is prevalent in north america.

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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About B40Overview

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.