A92 vs B33.1
A92 and B33.1 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 A92
Ross River disease (B33.1)
A92
Other mosquito-borne viral fevers
Not billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- A90-A99
B33.1
Ross River disease
Billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- B25-B34
Use when the record says
- Epidemic polyarthritis and exanthema
- Ross River fever
Indexed under
- Ross River disease or fever
- Disease, diseased › Ross River
- Fever › Ross River (inanition) (of unknown origin) (persistent) (with chills) (with rigor)
- Polyarthritis, polyarthropathy › epidemic
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