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I21 vs I82.90

I21 (Acute myocardial infarction) compared with I82.90 (Acute embolism and thrombosis of unspecified vein), 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 can be reported together when both conditions are documented, because I82.90 lists I21 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named and billing status.I21 is “Acute myocardial infarction”; I82.90 is “Acute embolism and thrombosis of unspecified vein”. I21 is a non-billable header; I82.90 is billable.

Registry fact

Can these codes be reported together?

Yes, when both are documented.I82.90 lists I21 under Excludes2: “coronary (I21-I25)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.I82.90’s tabular entry: “coronary (I21-I25)”. The note covers I21.

Official ruleGuide: Excludes1 vs Excludes2

Is one a parent or header code?

One is a header.I21 is a non-billable header, but I82.90 is not one of its subdivisions.

Registry fact

Nothing found in 3 other checks; 1 check does not apply
Is there an Excludes1 relationship?

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

Official rule

Is one more specific?

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

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

I82.90
Acute embolism and thrombosis of unspecified vein
↔
I21
Acute myocardial infarction

What we found

Yes, when both are documented.I82.90 carries an Excludes2 note covering I21: “coronary (I21-I25)”

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 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
I21

Acute myocardial infarction

I82.90

Acute embolism and thrombosis of unspecified vein

StatusDiffers
I21
Non-billable header

A header is not reported on a claim; a code beneath it is.

Report instead: I21.01, I21.02, I21.09, I21.11, I21.19

I82.90
Billable
Excludes2Differs
I21
  • old myocardial infarction (I25.2)
  • postmyocardial infarction syndrome (I24.1)
  • subsequent type 1 myocardial infarction (I22.-)
I82.90
  • venous embolism and thrombosis (of):
  • cerebral (I63.6, I67.6)
  • coronary (I21-I25)
  • intracranial and intraspinal, septic or NOS (G08)
  • intracranial, nonpyogenic (I67.6)
  • intraspinal, nonpyogenic (G95.1)
  • mesenteric (K55.0-)
  • portal (I81)
  • pulmonary (I26.-)
Code firstDiffers
I21

None at this code

I82.90
  • venous embolism and thrombosis complicating:
  • abortion, ectopic or molar pregnancy (O00-O07, O08.7)
  • pregnancy, childbirth and the puerperium (O22.-, O87.-)
Use additional codeDiffers
I21
  • code, if applicable, to identify:
  • exposure to environmental tobacco smoke (Z77.22)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (Z92.82)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)
I82.90

None at this code

Code alsoDiffers
I21
  • the presence of hypertension (I10-I1A)
I82.90

None at this code

CategoryDiffers
I21

Is itself a category

I82.90

I82 Other venous embolism and thrombosis

ChapterSame for both

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

IncludesDiffers
I21
  • cardiac infarction
  • coronary (artery) embolism
  • coronary (artery) occlusion
  • coronary (artery) rupture
  • coronary (artery) thrombosis
  • infarction of heart, myocardium, or ventricle
  • myocardial infarction specified as acute or with a stated duration of 4 weeks (28 days) or less from onset
I82.90
  • Embolism of vein NOS
  • Thrombosis (vein) NOS

No Excludes1 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.

Edit this comparisonCheck a whole claim

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