Excludes1 pair
A90 vs A91
A90 and A91 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 A90
dengue hemorrhagic fever (A91)
A90
Dengue fever [classical dengue]
Billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- A90-A99
Indexed under
- Dengue (classical) (fever)
- Fever › Aden (dengue)
- Fever › breakbone
- Fever › dandy
- Fever › dengue (virus)
A91
Dengue hemorrhagic fever
Billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- A90-A99
Indexed under
- Bangkok hemorrhagic fever
- Singapore hemorrhagic fever
- Southeast Asian hemorrhagic fever
- Thailand hemorrhagic fever
- Dengue › hemorrhagic
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