Alphabetic Index FY2027

T33

Superficial frostbite

FY2027Chapter 19: Injury, poisoning and certain other consequences of external causes/T33–T34 Frostbite

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

T33 is a non-billable ICD-10-CM code category for superficial frostbite. 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 T33.0 Superficial frostbite of head; T33.1 Superficial frostbite of neck; T33.2 Superficial frostbite of thorax; T33.3 Superficial frostbite of abdominal wall, lower back and pelvis and 6 more. Its coding notes include a Use additional code instruction and 3 Excludes2 entries.

7th characters

Every code below needs one of these.

The appropriate 7th character is to be added to each code from category T33

  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

Guidelines tip

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

Use additional code

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

Also from chapter/block level (1 note)
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.

Also from chapter/block level (3 notes)
Inherited from T33–T34 Frostbite
  • hypothermia and other effects of reduced temperature (T68, T69.-)
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
  • frostbite with partial 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 T33 10