Q27.8 vs Q28
Q27.8 and Q28 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 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 (congenital)
- Aberrant › subclavian artery (congenital)
- Aberrant › veinNEC (congenital)
- Absence › artery (of) (organ or part) (complete or partial)
- Absence › veincongenital NEC (of) (organ or part) (complete or partial)
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