FY2027
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Excludes1 pair

I67.1 vs Q28-

I67.1 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 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 (congenital) (nonruptured)
  • Aneurysm › brain
  • Aneurysm › cavernous sinus
  • Aneurysm › circle of Willis
  • Aneurysm › miliary (congenital)
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