2026 ICD-10-CM Diagnosis Code S21.019ALaceration without foreign body of unspecified breast, initial encounter

ICD-10-CM Codes›S00–T88›S20-S29›S21

ICD-10-CM S21.019A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S21.019A is a billable ICD-10-CM diagnosis code for laceration without foreign body of unspecified breast, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 604 through 605, 963 through 965. Coders also document this condition as laceration of breast. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Open wounds of trunk, initial encounter.

Code Identity

ICD-10-CM Code
S21.019A
Billable Status
Yes — Valid for Submission
Code Describes
Laceration without foreign body of unspecified breast, initial encounter
Short Description
Laceration without foreign body of unsp breast, init encntr
Parent Code
S21.019
Laceration without foreign body of unspecified breast

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS20-S29Injuries to the thorax
CategoryS21Open wound of thorax
This CodeS21.019ALaceration without foreign body of unspecified breast, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Laceration of breast
  • Stab wound of breast
  • Stab wound of chest

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Open wound of thorax (S21). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ013
Open wounds of trunk, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Wounds and Injuries

An injury is damage to your body. It is a general term that refers to harm caused by accidents, falls, hits, weapons, and more. In the U.S., millions of people injure themselves every year. These injuries range from minor to life-threatening.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert S21.019A to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
879.0 Open wound of breast
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About S21.019AOverview

Is S21.019A (Laceration without foreign body of unspecified breast) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report laceration without foreign body of unspecified breast, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in S21.019A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for laceration without foreign body of unspecified breast, such as an emergency visit or first evaluation.

What MS-DRG does S21.019A group to?

When laceration without foreign body of unspecified breast, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 604, 605, 963, 964, 965, with relative weights from 0.9160 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of S21.019A?

Under the General Equivalence Mappings, laceration without foreign body of unspecified breast, initial encounter converts to ICD-9-CM 879.0 (open wound of breast). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.