B52 vs B53.1
B52 and B53.1 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 B53.1
Malaria due to simian plasmodia with Plasmodium malariae (B52.-)
B52
Plasmodium malariae malaria
Not billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- B50-B64
Use when the record says
- mixed infections of Plasmodium malariae with other Plasmodium species, except Plasmodium falciparum and Plasmodium vivax
B53.1
Malaria due to simian plasmodia
Billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- B50-B64
Indexed under
- Monkey malaria
- Simian malaria
- Malaria, malarial › Plasmodium › simian (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