Alphabetic Index FY2027

T21

Burn and corrosion of trunk

FY2027Chapter 19: Injury, poisoning and certain other consequences of external causes/T20–T25 Burns and corrosions of external body surface, specified by site

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

T21 is a non-billable ICD-10-CM code category for burn and corrosion of trunk. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are T21.0 Burn of unspecified degree of trunk, T21.1 Burn of first degree of trunk, T21.2 Burn of second degree of trunk, T21.3 Burn of third degree of trunk and 4 more. Its coding notes include a Use additional code instruction and 5 Excludes2 entries.

7th characters

Every code below needs one of these.

The appropriate 7th character is to be added to each code from category T21

  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

Guidelines tips

From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.

The 7th character depends on whether the patient is in active treatment, not on who sees the patient. An aftercare Z code is not used for injury aftercare.

Guidelines I.C.19.aInjuries: application of 7th charactersRead the official text

Burns are classified by depth, extent and agent. Burns of the same site and side but different degrees take the highest degree. Non-healing burns are coded as acute burns.

Guidelines I.C.19.dBurns: depth, same site, healing and infectionRead the official text

Late effects of burns are coded with 7th character S, and a current burn and a sequela of an old burn can be coded together. An external cause code is used with burns.

Guidelines I.C.19.d.7; I.C.19.d.8; I.C.19.d.9Burn sequelae and external causeRead the official text

Use additional code

Add the listed code as a secondary code, if known.

Also from chapter/block level (2 notes)
Inherited from T20–T25 Burns and corrosions of external body surface, specified by site
  • code from category T31 or T32 to identify extent of body surface involved
Inherited from Chapter 19 Injury, poisoning and certain other consequences of external causes
  • code to identify any retained foreign body, if applicable (Z18.-)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

This code
  • 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)
Also from chapter/block level (2 notes)
Inherited from Chapter 19 Injury, poisoning and certain other consequences of external causes
  • birth trauma (P10-P15)
  • obstetric trauma (O70-O71)

Includes

Further defines or gives examples of the content of the category.

This code
  • burns and corrosion of hip region
Also from chapter/block level (3 notes)
Inherited from T20–T25 Burns and corrosions of external body surface, specified by site
  • burns and corrosions of first degree [erythema]
  • burns and corrosions of second degree [blisters][epidermal loss]
  • burns and corrosions of third degree [deep necrosis of underlying tissue] [full- thickness skin loss]

Notes

Also from chapter/block level (2 notes)
Inherited from Chapter 19 Injury, poisoning and certain other consequences of external causes
  • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
  • The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

More specific codes under T21 8