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I21.A9 vs I25.2

I21.A9 (Other myocardial infarction type) compared with I25.2 (Old myocardial infarction), from the official CMS tabular data.

Summary

These codes can be reported together when both conditions are documented, because I21.A9 lists I25.2 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named.I21.A9 is “Other myocardial infarction type”; I25.2 is “Old myocardial infarction”.

Registry fact

Can these codes be reported together?

Yes, when both are documented.I21.A9 lists I25.2 under Excludes2: “old myocardial infarction (I25.2)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code.

Official rule

Is there an Excludes2 relationship?

Yes.I21.A9’s tabular entry: “old myocardial infarction (I25.2)”. The note covers I25.2.

Official ruleGuide: Excludes1 vs Excludes2

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?

Informational

Excludes2 relationship

I21.A9
Other myocardial infarction type
↔
I25.2
Old myocardial infarction

What we found

Yes, when both are documented.I21.A9 carries an Excludes2 note covering I25.2: “old myocardial infarction (I25.2)”

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.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 FY2026

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

I21.A9Other myocardial infarction typeI25.2Old myocardial infarction
Billing statusBillableBillable
ClassificationI00-I99 — Diseases of the Circulatory System (I00-I99)I00-I99 — Diseases of the Circulatory System (I00-I99)
DefinitionOther myocardial infarction type is a billable ICD-10-CM diagnosis code (I21.A9).Old myocardial infarction is a billable ICD-10-CM diagnosis code (I25.2).
Includes
cardiac infarction
coronary (artery) embolism
coronary (artery) occlusion
coronary (artery) rupture
Healed myocardial infarction
Past myocardial infarction diagnosed by ECG or other investigation, but currently presenting no symptoms
Excludes2
old myocardial infarction (I25.2)
postmyocardial infarction syndrome (I24.1)
subsequent type 1 myocardial infarction (I22.-)
non-ischemic myocardial injury (I5A)
Code first
, if applicable, postprocedural myocardial infarction following cardiac surgery (I97.190), or postprocedural myocardial infarction during cardiac surgery (I97.790)
—
Use additional code
code, if applicable, to identify:
exposure to environmental tobacco smoke (Z77.22)
history of tobacco dependence (Z87.891)
code to identify:
chronic total occlusion of coronary artery (I25.82)
exposure to environmental tobacco smoke (Z77.22)
Code also
complication, if known and applicable, such as:
(acute) stent occlusion (T82.897-)
(acute) stent stenosis (T82.855-)
(acute) stent thrombosis (T82.867-)
cardiac arrest due to underlying cardiac condition (I46.2)
complication of percutaneous coronary intervention (PCI) (I97.89)
occlusion of coronary artery bypass graft (T82.218-)
the presence of hypertension (I10-I1A)
the presence of hypertension (I10-I1A)

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.

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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