Is ICD-10-CM code B46 billable?

No, B46 (Zygomycosis) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code B46 belong to?

B46 belongs to Chapter 1 of the ICD-10-CM tabular list: A00–B99 (Certain Infectious and Parasitic Diseases).

B46Not billable, use a more specific code below

Zygomycosis

In Mycoses (B35-B49), chapter 1: Certain Infectious and Parasitic Diseases

8 billable codes under B46: all are an MCC; all map to HCC 6 (Opportunistic Infections).A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment. An HCC counts toward a Medicare Advantage patient's risk score.

Instructional notes

Also applies, from Mycoses (B35-B49)

These notes sit on B35-B49 and apply to every code under it, including B46.

Excludes2: not included here, code separately if applicable

hypersensitivity pneumonitis due to organic dust (J67.-)
mycosis fungoides (C84.0-)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Rules for coding infections and parasitic diseases, including HIV, organism and drug resistance codes, sepsis and septic shock, MRSA, Zika, and COVID-19.

Human Immunodeficiency Virus (HIV) Infections (page 19)
Infectious agents as the cause of diseases classified to other chapters (page 22)
Infections resistant to antibiotics (page 22)
Sepsis, Severe Sepsis, and Septic Shock (page 23)
Methicillin Resistant Staphylococcus aureus (MRSA) Conditions (page 27)
Zika virus infections (page 28)
Coronavirus infections (page 28)

Read Section I.C.1 (page 19)

All codes under B46

B46 can't be used on a claim. Pick a billable code below; grey headings group them.

B46 MS-DRGs

As the principal diagnosis, all 8 billable codes under B46 group to MS-DRG 791, 793, 867, 868, or 869 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

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.

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.