S21.012S vs S21.019S

S21.012S (Laceration without foreign body of left breast, sequela) compared with S21.019S (Laceration without foreign body of unspecified breast, sequela), from the official CMS tabular data.

Summary

These codes name the same condition on opposite sides of the body, so the documented side decides which one applies.

MedCoder-derived

What is different?

Title wording.The titles differ in one word, “left” (S21.012S) versus “unspecified” (S21.019S): S21.012S is “Laceration without foreign body of left breast, sequela”; S21.019S is “Laceration without foreign body of unspecified breast, sequela”.

Registry fact

Can these codes be reported together?

One side per condition.S21.012S and S21.019S name the same condition on opposite sides of the body. Same category and title, differing only in which side is affected — the documentation decides which one applies, and a bilateral code is reported only where the code set provides one.

MedCoder-derivedGuide: Laterality coding

Is there an Excludes1 relationship?

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

Official rule

Is there an Excludes2 relationship?

None.Neither entry carries an Excludes2 note that names the other code.

Official rule

Is one more specific?

Yes.S21.012S’s title names the condition; S21.019S’s title is the unspecified form (“Laceration without foreign body of unspecified breast, sequela”).

MedCoder-derivedGuide: Other vs unspecified (NEC vs NOS)

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?

Yes.Same condition, opposite side. S21.012S and S21.019S name the same condition on opposite sides of the body.

MedCoder-derivedGuide: Laterality coding

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?

Review

Laterality relationship

S21.012S

Left

Laceration without foreign body of left breast, sequela

↔

S21.019S

Unspecified

Laceration without foreign body of unspecified breast, sequela

What we found

Same condition, opposite side.S21.012S and S21.019S name the same condition on opposite sides of the body.

Same category and title, differing only in which side is affected — the documentation decides which one applies, and a bilateral code is reported only where the code set provides one.

What to review

Report the side the documentation names. Where the code set provides a bilateral code and both sides are documented, use it instead of the pair.

Guide: Laterality coding Check these on a claim

Why it matters

These codes share a category and title and differ only in the side affected. The documentation decides which applies, and a bilateral code is reported only where the code set provides one.

Source / rule

ICD-10-CM tabular list (laterality variant derived from the code title)

Official guidance behind these answers

Section I.B.13 — Laterality · applies to: Laterality
Some ICD-10-CM codes indicate laterality, specifying whether the condition occurs on the left, right or is bilateral. If no bilateral code is provided and the condition is bilateral, assign separate codes for both the left and right side. If the side is not identified in the medical record, assign the code for the unspecified side. When a patient has a bilateral condition and each side is treated during separate encounters, assign the "bilateral" code (as the condition still exists on both sides), including for the encounter to treat the first side. For the second encounter for treatment after one side has previously been treated and the condition no longer exists on that side, assign the appropriate unilateral code for the side where the condition still exists (e.g., cataract surgery performed on each eye in separate encounters). The bilateral code would not be assigned for the subsequent encounter, as the patient no longer has the condition in the previously-treated site. If the treatment on the first side did not completely resolve the condition, then the bilateral code would still be appropriate. When laterality is not documented by the patient’s provider, code assignment for the affected side may be based on medical record documentation from other clinicians. If there is conflicting medical record documentation regarding the affected side, the patient’s provider should be queried for clarification. […]
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

	S21.012SLaceration without foreign body of left breast, sequela	S21.019SLaceration without foreign body of unspecified breast, sequela
Billing status	Billable	Billable
Classification	S00-T88 — Injury, poisoning and certain other consequences of external causes	S00-T88 — Injury, poisoning and certain other consequences of external causes
Definition	Laceration without foreign body of left breast, sequela is a billable ICD-10-CM diagnosis code (S21.012S).	Laceration without foreign body of unspecified breast, sequela is a billable ICD-10-CM diagnosis code (S21.019S).
7th character	The appropriate 7th character is to be added to each code from category S21	The appropriate 7th character is to be added to each code from category S21
Includes	injuries of breast injuries of chest (wall) injuries of interscapular area	injuries of breast injuries of chest (wall) injuries of interscapular area

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 (FY2026). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources