Skip to main content

I72.0 vs Q28.1

I72.0 (Aneurysm of carotid artery) compared with Q28.1 (Other malformations of precerebral vessels), from the official CMS tabular data.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Summary

These codes should not be reported together because Q28.1’s tabular entry lists I72.0 under Excludes1.

Official rule
What is different?

The conditions named and chapter.I72.0 is “Aneurysm of carotid artery”; Q28.1 is “Other malformations of precerebral vessels”. I72.0 sits in I00-I99 — Diseases of the Circulatory System (I00-I99); Q28.1 in Q00-QA1 — Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-QA1).

Registry fact

Can these codes be reported together?

No.Q28.1’s entry carries an Excludes1 note covering I72.0: “ruptured malformation of precerebral vessels (I72.0)”. Both may be reported only when the documentation shows the two conditions are unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

Yes.Q28.1’s tabular entry: “ruptured malformation of precerebral vessels (I72.0)”. The note covers I72.0.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.I72.0’s tabular entry: “dissection of precerebral artery, congenital (nonruptured) (Q28.1)”. The note covers Q28.1.

Official ruleGuide: Excludes1 vs Excludes2

Nothing found in 3 other checks; 1 check does not apply
Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Is one a parent or header code?

No.Both are billable codes, and neither contains the other.

Registry fact

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Excludes1 — generally not reported together

Excludes1 conflict

Q28.1
Other malformations of precerebral vessels
↔
I72.0
Aneurysm of carotid artery

What we found

No — do not report together.Q28.1 carries an Excludes1 note covering I72.0: “ruptured malformation of precerebral vessels (I72.0)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

What to review

Report one of the two. Both may be reported only when the documentation shows the two conditions are unrelated to each other.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes1 note means the two conditions are not ordinarily reported together for the same encounter, because the classification treats them as mutually exclusive forms of the same condition. The documented exception is when the two conditions are unrelated to each other.

Source / rule

CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a

Informational

Excludes2 relationship

I72.0
Aneurysm of carotid artery
↔
Q28.1
Other malformations of precerebral vessels

What we found

Yes, when both are documented.I72.0 carries an Excludes2 note covering Q28.1: “dissection of precerebral artery, congenital (nonruptured) (Q28.1)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

  • Section I.A.12.a — Excludes1 · applies to: Excludes1

    A type 1 Excludes note is a pure excludes note. It means “NOT CODED HERE!” An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition. An exception to the Excludes1 definition is the circumstance when the two conditions are unrelated to each other. If it is not clear whether the two conditions involving an Excludes1 note are related or not, query the provider. For example, code F45.8, Other somatoform disorders, has an Excludes1 note for "sleep related teeth grinding (G47.63)," because "teeth grinding" is an inclusion term under F45.8. Only one of these two codes should be assigned for teeth grinding. However psychogenic dysmenorrhea is also an inclusion term under F45.8, and a patient could have both this condition and sleep related teeth grinding. In this case, the two conditions are clearly unrelated to each other, and so it would be appropriate to report F45.8 and G47.63 together.

    ICD-10-CM Official Guidelines FY2027

  • Section I.A.12.b — Excludes2 · applies to: Excludes2

    A type 2 Excludes note represents “Not included here.” An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

    ICD-10-CM Official Guidelines FY2027

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

Similar descriptions do not make codes interchangeable. The documentation and the official instructions decide which code applies.

Official descriptionDiffers
I72.0

Aneurysm of carotid artery

Q28.1

Other malformations of precerebral vessels

StatusSame for both
Billable
Excludes1Differs
I72.0
  • aneurysm of internal carotid artery, intracranial portion (I67.1)
  • aneurysm of internal carotid artery NOS (I67.1)
Q28.1
  • congenital aneurysm NOS (Q27.8)
  • congenital coronary aneurysm (Q24.5)
  • ruptured cerebral arteriovenous malformation (I60.8)
  • ruptured malformation of precerebral vessels (I72.0)
Excludes2Differs
I72.0
  • acquired aneurysm (I77.0)
  • aneurysm (of) aorta (I71.-)
  • aneurysm (of) arteriovenous NOS (Q27.3-)
  • carotid artery dissection (I77.71)
  • cerebral (nonruptured) aneurysm (I67.1)
  • coronary aneurysm (I25.4)
  • coronary artery dissection (I25.42)
  • dissection of artery NEC (I77.79)
  • dissection of precerebral artery, congenital (nonruptured) (Q28.1)
  • heart aneurysm (I25.3)
  • iliac artery dissection (I77.72)
  • precerebral artery, congential (nonruptured) (Q28.1)
  • pulmonary artery aneurysm (I28.1)
  • renal artery dissection (I77.73)
  • retinal aneurysm (H35.0)
  • ruptured cerebral aneurysm (I60.7)
  • varicose aneurysm (I77.0)
  • vertebral artery dissection (I77.74)
Q28.1
  • congenital peripheral aneurysm (Q27.8)
  • congenital pulmonary aneurysm (Q25.79)
  • congenital retinal aneurysm (Q14.1)
CategoryDiffers
I72.0

I72 Other aneurysm

Q28.1

Q28 Other congenital malformations of circulatory system

ChapterDiffers
I72.0

I00-I99 — Diseases of the Circulatory System (I00-I99)

Q28.1

Q00-QA1 — Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-QA1)

IncludesDiffers
I72.0
  • aneurysm (cirsoid) (false) (ruptured)
  • Aneurysm of common carotid artery
  • Aneurysm of external carotid artery
  • Aneurysm of internal carotid artery, extracranial portion
Q28.1
  • Congenital malformation of precerebral vessels NOS
  • Congenital precerebral aneurysm (nonruptured)

No Code first, Use additional code, Code also and 7th character note at either code.

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on. In a row that differs, each code’s own notes are listed under it, and the notes every code shares are listed once beneath them.

Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources