B04 Monkeypox

The ICD-10-CM code for Monkeypox is B04 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

1: Certain infectious and parasitic diseases (A00-B99)

Section

B00-B09: Viral infections characterized by skin and mucous membrane lesions (B00-B09)

Category B04

1 code (1 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to B04:

• Monkeypox
• Mpox

Inclusion Terms

• Mpox

U.S. Hospital Utilization

• An estimated 370 U.S. inpatient stays in 2023 included B04 among the documented diagnoses.
• 145 stays listed it as the principal diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

HIV Infections (TOC entry)

a. Human Immunodeficiency Virus (HIV) Infections .............................................................. 19

Infectious agents causing diseases in other chapters (TOC)

b. Infectious agents as the cause of diseases classified to other chapters ................................. 22

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)

Cite This Page

Reference B04 with the canonical source and edition:

B04 — Monkeypox. ICD-10 Coding Pro (ICD-10-CM FY2026). https://icd10codingpro.com/codes/B04

Canonical URL: https://icd10codingpro.com/codes/B04