I67.1 vs Q28
I67.1 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 I67.1
congenital cerebral aneurysm, nonruptured (Q28.-)
I67.1
Cerebral aneurysm, nonruptured
Billable
- Chapter 9
- Diseases of the circulatory system
- Section
- I60-I69
Use when the record says
- Cerebral aneurysm NOS
- Cerebral arteriovenous fistula, acquired
- Internal carotid artery aneurysm, intracranial portion
- Internal carotid artery aneurysm, NOS
Indexed under
- Aneurysm › berry (anastomotic) (artery) (cirsoid) (diffuse) (false) (fusiform) (multiple) (saccular)
- Aneurysm › brain (anastomotic) (artery) (cirsoid) (diffuse) (false) (fusiform) (multiple) (saccular)
- Aneurysm › cavernous sinus (anastomotic) (artery) (cirsoid) (diffuse) (false) (fusiform) (multiple) (saccular)
- Aneurysm › circle of Willis (anastomotic) (artery) (cirsoid) (diffuse) (false) (fusiform) (multiple) (saccular)
- Aneurysm › miliary (anastomotic) (artery) (cirsoid) (diffuse) (false) (fusiform) (multiple) (saccular)
Q28
Other congenital malformations of circulatory system
Not billable
- Chapter 17
- Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
- Section
- Q20-Q28
These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.
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