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ICD-10-CM 2027 diagnosis code

S21.05Open bite of breast

Not billable — use a more specific codeRequires 7th character

S21.05 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.

Looking up by condition? See ICD-10 code for Breast bite.

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 S21.05

S21.05 is the ICD-10-CM diagnosis code for open bite 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 (open wound of breast), S21.05 is specifically for open bite of breast. Related codes cover unspecified open wound of breast (S21.00), 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) and puncture wound with foreign body of breast (S21.04).

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.

Don't report S21.05 together with the conditions in its Excludes1 note: superficial bite of breast (S20.17).

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

Coding notes

Applicable toConditions and synonyms classified to this code
  • Bite of breast NOS
Excludes1Not coded here — never report together with this code
  • superficial bite of breast (S20.17)

Notes that apply from higher levels

Instructions written at a parent level also apply to S21.05.

› 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 S21.05.

Codes whose notes reference S21.05

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about S21.05

Is S21.05 billable?

No. S21.05 is a header code. Report one of its more specific subcodes instead.