2026 ICD-10-CM Diagnosis Code B33Other viral diseases, not elsewhere classified

ICD-10-CM Codes›A00–B99›B25-B34›B33

ICD-10-CM B33
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B33 is a non-billable ICD-10-CM category code for other viral diseases, not elsewhere classified, so it cannot be submitted on claims. Use a more specific code from this category instead, such as B33.0, B33.1, B33.20, and B33.21.

Code Identity

ICD-10-CM Code
B33
Billable Status
No — Non-Billable Category
Code Describes
Other viral diseases, not elsewhere classified
Chapter
B25-B34
Other viral diseases

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB25-B34Other viral diseases
CategoryB33Other viral diseases, not elsewhere classified
This CodeB33Other viral diseases, not elsewhere classified

Specific Coding for Other viral diseases, not elsewhere classifiedOverview

Non-specific codes like B33 require more characters. Use one of these billable codes instead:

  • Use B33.0 for Epidemic myalgia

  • Use B33.1 for Ross River disease

  • B33.2 for Viral carditis

  • Use B33.20 for Viral carditis, unspecified

  • Use B33.21 for Viral endocarditis

  • Use B33.22 for Viral myocarditis

  • Use B33.23 for Viral pericarditis

  • Use B33.24 for Viral cardiomyopathy

  • Use B33.3 for Retrovirus infections, not elsewhere classified

  • Use B33.4 for Hantavirus (cardio)-pulmonary syndrome [HPS] [HCPS]

  • Use B33.8 for Other specified viral diseases

Patient EducationClinical

Viral Infections

Viruses are very tiny germs. They are made of genetic material (either DNA or RNA) inside of a protein coating. There are a huge number of viruses on earth. Only a small number of them can infect humans. Those viruses can infect our cells, which may cause disease.

The full article covers:

  • What are viruses?
  • How are viruses spread?
  • How do viruses cause disease?
  • What are the treatments for viral infections?
  • Can viral infections be prevented?

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 B33Overview

Is B33 (Other viral diseases, not elsewhere classified) a billable code?

No. This is a category header that groups the codes for other viral diseases, not elsewhere classified, and headers cannot be submitted on claims. Claims for other viral diseases, not elsewhere classified need a more specific code from this category, such as B33.0, B33.1, and B33.20.