2026 ICD-10-CM Diagnosis Code B46.4Disseminated mucormycosis

ICD-10-CM Codes›A00–B99›B35-B49›B46

ICD-10-CM B46.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B46.4 is a billable ICD-10-CM diagnosis code for disseminated mucormycosis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 867 through 869. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Fungal infections.

Code Identity

ICD-10-CM Code
B46.4
Billable Status
Yes — Valid for Submission
Code Describes
Disseminated mucormycosis
Short Description
Disseminated mucormycosis
Same as the full description in the CMS dataset.
Parent Code
B46
Zygomycosis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB35-B49Mycoses
CategoryB46Zygomycosis
This CodeB46.4Disseminated mucormycosis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Disseminated mucormycosis

Tabular List NotesGuidance

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

Inclusion Terms

  • Generalized mucormycosis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Mucormycosis
      • disseminated
    • Mucormycosis
      • generalized

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INF004
Fungal infections
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Zygomycosis

    infection in humans and animals caused by fungi in the class zygomycetes. it includes mucormycosis and entomophthoramycosis. the latter is a tropical infection of subcutaneous tissue or paranasal sinuses caused by fungi in the order entomophthorales. phycomycosis, closely related to zygomycosis, describes infection with members of phycomycetes, an obsolete classification.

  • Mucormycosis

    infection in humans and animals caused by any fungus in the order mucorales (e.g., rhizopus; mucor; cunninghamella; apophysomyces; absidia; saksenaea and rhizomucor) there are many clinical types associated with infection including central nervous system, lung, gastrointestinal tract, skin, orbit and paranasal sinuses. in humans, it usually occurs as an opportunistic infection.

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.

Convert B46.4 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
117.7 Zygomycosis
Approximate The match is approximate rather than exact.

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 B46.4Overview

Is B46.4 (Zygomycosis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report disseminated mucormycosis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does B46.4 group to?

When disseminated mucormycosis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 867, 868, 869, with relative weights from 0.7297 to 2.0932 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of B46.4?

Under the General Equivalence Mappings, disseminated mucormycosis converts to ICD-9-CM 117.7 (zygomycosis). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.