B33.3 vs B34
B33.3 and B34 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on B34
retrovirus infection NOS (B33.3)
B33.3
Retrovirus infections, not elsewhere classified
BillableUnspecified
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- B25-B34
Use when the record says
- Retrovirus infection NOS
Indexed under
- Infection, infected, infective › retrovirus (opportunistic)
- Human › T-cell lymphotropic virus › type-1infection
- Infection, infected, infective › human › T-cell lymphotropic virus type-1 (opportunistic)
B34
Viral infection of unspecified site
Not billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- B25-B34
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027