Excludes1 pair
Q27.8 vs Q28-
Q27.8 and Q28 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 Q28
congenital aneurysm NOS (Q27.8)
Q27.8
Other specified congenital malformations of peripheral vascular system
BillableUnspecified
- Chapter 17
- Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
- Section
- Q20-Q28
Use when the record says
- Absence of peripheral vascular system
- Atresia of peripheral vascular system
- Congenital aneurysm (peripheral)
- Congenital stricture, artery
- Congenital varix
Indexed under
- Aberrant › artery (peripheral)
- Aberrant › subclavian artery
- Aberrant › vein NEC (peripheral)
- Absence › artery (congenital) (peripheral)
- Absence › vein congenital NEC (peripheral)
Q28
Other congenital malformations of circulatory system
Not billable
- Chapter 17
- Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
- Section
- Q20-Q28
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