Excludes1 pair
A20- vs A28.2
A20 and A28.2 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.
The official note, declared on A28.2
plague (A20.-)
A20
Plague
Not billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- A20-A28
Use when the record says
- infection due to Yersinia pestis
A28.2
Extraintestinal yersiniosis
Billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- A20-A28
Indexed under
- Pseudotuberculosis
- Sepsis › extraintestinal yersiniosis
- Yersiniosis › extraintestinal
- Infection, infected, infective › Yersinia › pseudotuberculosis
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