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S00.4 vs S09.399A

S00.4 (Superficial injury of ear) compared with S09.399A (Other specified injury of unspecified middle and inner ear, initial encounter), from the official CMS tabular data.

Summary

These codes can be reported together when both conditions are documented, because S09.399A lists S00.4 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named and billing status.S00.4 is “Superficial injury of ear”; S09.399A is “Other specified injury of unspecified middle and inner ear, initial encounter”. S00.4 is a non-billable header; S09.399A is billable.

Registry fact

Can these codes be reported together?

Yes, when both are documented.S09.399A lists S00.4 under Excludes2: “injury to external ear (S00.4-, S01.3-, S08.1-)”. 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. S00.4 carries 4 Excludes1 notes and S09.399A carries 1 Excludes1 note covering other codes; the side-by-side table quotes them.

Official rule

Is there an Excludes2 relationship?

Yes.S09.399A’s tabular entry: “injury to external ear (S00.4-, S01.3-, S08.1-)”. The note covers S00.4.

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?

One is a header.S00.4 is a non-billable header, but S09.399A is not one of its subdivisions.

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

S09.399A
Other specified injury of unspecified middle and inner ear, initial encounter
↔
S00.4
Superficial injury of ear

What we found

Yes, when both are documented.S09.399A carries an Excludes2 note covering S00.4: “injury to external ear (S00.4-, S01.3-, S08.1-)”

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.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

S00.4Superficial injury of earS09.399AOther specified injury of unspecified middle and inner ear, initial encounter
Billing statusNon-billable header

Report instead: S00.401A, S00.401D, S00.401S, S00.402A, S00.402D

Billable
ClassificationS00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)
DefinitionSuperficial injury of ear is a non-billable ICD-10-CM category code (S00.4).Other specified injury of unspecified middle and inner ear, initial encounter is a billable ICD-10-CM diagnosis code (S09.399A).
7th characterThe appropriate 7th character is to be added to each code from category S00The appropriate 7th character is to be added to each code from category S09
Includes
injuries of ear
injuries of eye
injuries of face [any part]
injuries of gum
injuries of ear
injuries of eye
injuries of face [any part]
injuries of gum
Excludes1
diffuse cerebral contusion (S06.2-)
focal cerebral contusion (S06.3-)
injury of eye and orbit (S05.-)
open wound of head (S01.-)
injury to ear NOS (S09.91-)
Excludes2
burns and corrosions (T20-T32)
effects of foreign body in ear (T16)
effects of foreign body in larynx (T17.3)
effects of foreign body in mouth NOS (T18.0)
effects of foreign body in nose (T17.0-T17.1)
effects of foreign body in pharynx (T17.2)
effects of foreign body on external eye (T15.-)
frostbite (T33-T34)
insect bite or sting, venomous (T63.4)
injury to external ear (S00.4-, S01.3-, S08.1-)
burns and corrosions (T20-T32)
effects of foreign body in ear (T16)
effects of foreign body in larynx (T17.3)
effects of foreign body in mouth NOS (T18.0)
effects of foreign body in nose (T17.0-T17.1)
effects of foreign body in pharynx (T17.2)
effects of foreign body on external eye (T15.-)
frostbite (T33-T34)
insect bite or sting, venomous (T63.4)
Code also
for any associated infection
for any associated infection

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