B33.3 Retrovirus infections, not elsewhere classified

The ICD-10-CM code for Retrovirus infections, not elsewhere classified is B33.3 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

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

Section

B25-B34: Other viral diseases (B25-B34)

Category B33

12 codes (10 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to B33.3:

• Infection, infected, infective (opportunistic) › retrovirus
• Human › T-cell lymphotropic virus › type-1 (HTLV-I) infection
• Infection, infected, infective (opportunistic) › human › T-cell lymphotropic virus type-1 (HTLV-1)

Inclusion Terms

• Retrovirus infection NOS

U.S. Hospital Utilization

• An estimated 85 U.S. inpatient stays in 2023 included B33.3 among the documented diagnoses.

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)