2026 ICD-10-CM Diagnosis Code T21Burn and corrosion of trunk

ICD-10-CM Codes›S00–T88›T20-T25›T21

ICD-10-CM T21
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T21 is a non-billable ICD-10-CM category code for burn and corrosion of trunk, so it cannot be submitted on claims. Use a more specific code from this category instead, such as T21.00XA, T21.00XD, T21.00XS, and T21.01XA.

Code Identity

ICD-10-CM Code
T21
Billable Status
No — Non-Billable Category
Code Describes
Burn and corrosion of trunk
Short Description
Burn and corrosion of trunk
Same as the full description in the CMS dataset.
Chapter
T20-T25
Burns and corrosions of external body surface, specified by site

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT20-T25Burns and corrosions of external body surface, specified by site
CategoryT21Burn and corrosion of trunk
This CodeT21Burn and corrosion of trunk

Specific Coding for Burn and corrosion of trunkOverview

Non-specific codes like T21 require more characters. Use one of these billable codes instead:

  • T21.0 for Burn of unspecified degree of trunk

  • T21.00 for Burn of unspecified degree of trunk, unspecified site

  • T21.01 for Burn of unspecified degree of chest wall

  • T21.02 for Burn of unspecified degree of abdominal wall

  • T21.03 for Burn of unspecified degree of upper back

  • T21.04 for Burn of unspecified degree of lower back

  • T21.05 for Burn of unspecified degree of buttock

  • T21.06 for Burn of unspecified degree of male genital region

  • T21.07 for Burn of unspecified degree of female genital region

  • T21.09 for Burn of unspecified degree of other site of trunk

  • T21.1 for Burn of first degree of trunk

  • T21.10 for Burn of first degree of trunk, unspecified site

  • T21.11 for Burn of first degree of chest wall

  • T21.12 for Burn of first degree of abdominal wall

  • T21.13 for Burn of first degree of upper back

  • T21.14 for Burn of first degree of lower back

  • T21.15 for Burn of first degree of buttock

  • T21.16 for Burn of first degree of male genital region

  • T21.17 for Burn of first degree of female genital region

  • T21.19 for Burn of first degree of other site of trunk

  • T21.2 for Burn of second degree of trunk

  • T21.20 for Burn of second degree of trunk, unspecified site

  • T21.21 for Burn of second degree of chest wall

  • T21.22 for Burn of second degree of abdominal wall

  • T21.23 for Burn of second degree of upper back

  • T21.24 for Burn of second degree of lower back

  • T21.25 for Burn of second degree of buttock

  • T21.26 for Burn of second degree of male genital region

  • T21.27 for Burn of second degree of female genital region

  • T21.29 for Burn of second degree of other site of trunk

  • T21.3 for Burn of third degree of trunk

  • T21.30 for Burn of third degree of trunk, unspecified site

  • T21.31 for Burn of third degree of chest wall

  • T21.32 for Burn of third degree of abdominal wall

  • T21.33 for Burn of third degree of upper back

  • T21.34 for Burn of third degree of lower back

  • T21.35 for Burn of third degree of buttock

  • T21.36 for Burn of third degree of male genital region

  • T21.37 for Burn of third degree of female genital region

  • T21.39 for Burn of third degree of other site of trunk

  • T21.4 for Corrosion of unspecified degree of trunk

  • T21.40 for Corrosion of unspecified degree of trunk, unspecified site

  • T21.41 for Corrosion of unspecified degree of chest wall

  • T21.42 for Corrosion of unspecified degree of abdominal wall

  • T21.43 for Corrosion of unspecified degree of upper back

  • T21.44 for Corrosion of unspecified degree of lower back

  • T21.45 for Corrosion of unspecified degree of buttock

  • T21.46 for Corrosion of unspecified degree of male genital region

  • T21.47 for Corrosion of unspecified degree of female genital region

  • T21.49 for Corrosion of unspecified degree of other site of trunk

  • T21.5 for Corrosion of first degree of trunk

  • T21.50 for Corrosion of first degree of trunk, unspecified site

  • T21.51 for Corrosion of first degree of chest wall

  • T21.52 for Corrosion of first degree of abdominal wall

  • T21.53 for Corrosion of first degree of upper back

  • T21.54 for Corrosion of first degree of lower back

  • T21.55 for Corrosion of first degree of buttock

  • T21.56 for Corrosion of first degree of male genital region

  • T21.57 for Corrosion of first degree of female genital region

  • T21.59 for Corrosion of first degree of other site of trunk

  • T21.6 for Corrosion of second degree of trunk

  • T21.60 for Corrosion of second degree of trunk, unspecified site

  • T21.61 for Corrosion of second degree of chest wall

  • T21.62 for Corrosion of second degree of abdominal wall

  • T21.63 for Corrosion of second degree of upper back

  • T21.64 for Corrosion of second degree of lower back

  • T21.65 for Corrosion of second degree of buttock

  • T21.66 for Corrosion of second degree of male genital region

  • T21.67 for Corrosion of second degree of female genital region

  • T21.69 for Corrosion of second degree of other site of trunk

  • T21.7 for Corrosion of third degree of trunk

  • T21.70 for Corrosion of third degree of trunk, unspecified site

  • T21.71 for Corrosion of third degree of chest wall

  • T21.72 for Corrosion of third degree of abdominal wall

  • T21.73 for Corrosion of third degree of upper back

  • T21.74 for Corrosion of third degree of lower back

  • T21.75 for Corrosion of third degree of buttock

  • T21.76 for Corrosion of third degree of male genital region

  • T21.77 for Corrosion of third degree of female genital region

  • T21.79 for Corrosion of third degree of other site of trunk

Coding GuidelinesGuidance

The ICD-10-CM makes a distinction between burns and corrosions. The burn codes are for thermal burns, except sunburns, that come from a heat source, such as a fire or hot appliance. The burn codes are also for burns resulting from electricity and radiation. Corrosions are burns due to chemicals. The guidelines are the same for burns and corrosions.

Sequence first the code that reflects the highest degree of burn when more than one burn is present.

  • When the reason for the admission or encounter is for treatment of external multiple burns, sequence first the code that reflects the burn of the highest degree.
  • When a patient has both internal and external burns, the circumstances of admission govern the selection of the principal diagnosis or first-listed diagnosis.
  • When a patient is admitted for burn injuries and other related conditions such as smoke inhalation and/or respiratory failure, the circumstances of admission govern the selection of the principal or first-listed diagnosis.

Current burns (T20-T25) are classified by depth, extent and by agent (X code). Burns are classified by depth as first degree (erythema), second degree (blistering), and third degree (full-thickness involvement).

Classify burns of the same local site (three-character category level, T20-T28) but of different degrees to the subcategory identifying the highest degree recorded in the diagnosis.

The appropriate 7th character is to be added to each code from block Burn and corrosion of trunk (T21). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Includes

  • burns and corrosion of hip region

Type 2 Excludes

  • burns and corrosion of axilla T22
  • burns and corrosion of scapular region T22
  • burns and corrosion of shoulder T22

7th Character Note

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

7th Character

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Patient EducationClinical

Burns

A burn is damage to your body's tissues caused by heat, chemicals, electricity, sunlight, or radiation. Scalds from hot liquids and steam, building fires and flammable liquids and gases are the most common causes of burns. Another kind is an inhalation injury, caused by breathing smoke.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About T21Overview

Is T21 (Burn and corrosion of trunk) a billable code?

No. This is a category header that groups the codes for burn and corrosion of trunk, and headers cannot be submitted on claims. Claims for burn and corrosion of trunk need a more specific code from this category, such as T21.00XA, T21.00XD, and T21.00XS.