B51 vs B53.0
B51 and B53.0 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 B53.0
Plasmodium ovale with Plasmodium vivax (B51.-)
B51
Plasmodium vivax malaria
Not billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- B50-B64
Use when the record says
- mixed infections of Plasmodium vivax with other Plasmodium species, except Plasmodium falciparum
B53.0
Plasmodium ovale malaria
Billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- B50-B64
Indexed under
- Fever › Plasmodium ovale (inanition) (of unknown origin) (persistent) (with chills) (with rigor)
- Malaria, malarial › ovale (fever)
- Malaria, malarial › Plasmodium › ovale (fever)
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