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ICD-10-CM 2027 diagnosis code

T21.7Corrosion of third degree of trunk

Not billable — use a more specific codeRequires 7th character

T21.7 is a header code, so it can't be reported by itself. Choose one of the 9 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 T21.7

T21.7 is the ICD-10-CM diagnosis code for corrosion of third degree of trunk. It belongs to category T21 (burn and corrosion of trunk), block T20-T25 (burns and corrosions of external body surface, specified by site) 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 9 subcodes must be used instead.

Within T21 (burn and corrosion of trunk), T21.7 is specifically for corrosion of third degree of trunk. Related codes cover burn of unspecified degree of trunk (T21.0), burn of first degree of trunk (T21.1), burn of second degree of trunk (T21.2), burn of third degree of trunk (T21.3), corrosion of unspecified degree of trunk (T21.4), corrosion of first degree of trunk (T21.5) and corrosion of second degree of trunk (T21.6).

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.

Code first: (T51-T65) to identify chemical and intent.

Use an additional code for: external cause code to identify place (Y92).

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 T21

  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

Coding notes

Code firstSequence the underlying condition first
  • (T51-T65) to identify chemical and intent
Use additional codeAdd a secondary code to fully describe the condition
  • external cause code to identify place (Y92)

Notes that apply from higher levels

Instructions written at a parent level also apply to T21.7.

› From T21 Burn and corrosion of trunk
Includes
  • burns and corrosion of hip region
Excludes2
  • burns and corrosion of axilla (T22.- with fifth character 4)
  • burns and corrosion of scapular region (T22.- with fifth character 6)
  • burns and corrosion of shoulder (T22.- with fifth character 5)

Broader instructions also apply from T20-T25 Burns and corrosions of external body surface, specified by site and Chapter 19: Injury, poisoning and certain other consequences of external causes.

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 T21.7

Is T21.7 billable?

No. T21.7 is a header code. Report one of its more specific subcodes instead.