ICD-10-CM 2027 diagnosis code

S21.00Unspecified open wound of breast

Not billable — use a more specific codeRequires 7th character

S21.00 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it and add the required 7th character.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About S21.00

S21.00 is the ICD-10-CM diagnosis code for unspecified open wound of breast. It belongs to category S21 (open wound of thorax), block S20-S29 (injuries to the thorax) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within S21.0, choose S21.00 (Unspecified open wound of breast) only when documentation doesn't support a more specific option: laceration without foreign body of breast (S21.01), laceration with foreign body of breast (S21.02), puncture wound without foreign body of breast (S21.03), puncture wound with foreign body of breast (S21.04) and open bite of breast (S21.05).

Codes in this range require a 7th character: A for initial encounter, D for subsequent encounter and S for sequela. Use placeholder "X" characters to fill any empty positions before the 7th character.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

7th character

The appropriate 7th character is to be added to each code from category S21

Ainitial encounter
Dsubsequent encounter
Ssequela

Notes that apply from higher levels

Instructions written at a parent level also apply to S21.00.

› From S21 Open wound of thorax

Excludes1

traumatic amputation (partial) of thorax (S28.1)

Code also

any associated injury, such as:
injury of heart (S26.-)
injury of intrathoracic organs (S27.-)
rib fracture (S22.3-, S22.4-)
spinal cord injury (S24.0-, S24.1-)
traumatic hemopneumothorax (S27.3)
traumatic hemothorax (S27.1)
traumatic pneumothorax (S27.0)
wound infection

Broader instructions also apply from S20-S29 Injuries to the thorax and Chapter 19: Injury, poisoning and certain other consequences of external causes.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to S21.00.

Wound, open › breast

Code history

2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about S21.00

Is S21.00 billable?: No. S21.00 is a header code. Report one of its more specific subcodes instead.