T21.5 – Corrosion of first degree of trunk

ICD-10-CM 2027 diagnosis code · Burns and corrosions of external body surface, specified by site

Non-billable header

ICD-10-CM code T21.5

Code: T21.5 (claims format: T215)
Description: Corrosion of first degree of trunk
Billable: No – use a more specific code below
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 19. Injury, poisoning and certain other consequences of external causes (S00-T88)
Block: T20-T25 Burns and corrosions of external body surface, specified by site
Parent codes: T21

Billable codes under T21.5

T21.5 is a header code and cannot be used on claims. Choose the most specific code:

T21.50 – Corrosion of first degree of trunk, unspecified siteHeader (more codes below)
T21.51 – Corrosion of first degree of chest wallHeader (more codes below)
T21.52 – Corrosion of first degree of abdominal wallHeader (more codes below)
T21.53 – Corrosion of first degree of upper backHeader (more codes below)
T21.54 – Corrosion of first degree of lower backHeader (more codes below)
T21.55 – Corrosion of first degree of buttockHeader (more codes below)
T21.56 – Corrosion of first degree of male genital regionHeader (more codes below)
T21.57 – Corrosion of first degree of female genital regionHeader (more codes below)
T21.59 – Corrosion of first degree of other site of trunkHeader (more codes below)

7th character values

Codes in this category need a 7th character to describe the encounter or episode of care (use placeholder X for empty positions).

Character	Meaning
`A`	initial encounter
`D`	subsequent encounter
`S`	sequela

Notes for T21.5

Code first:

(T51-T65) to identify chemical and intent

Use additional code:

external cause code to identify place (Y92)

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

T21 – Burn and corrosion of trunk

Includes:

burns and corrosion of hip region

Excludes2 (not included here):

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)

7th character note:

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

Block T20-T25

Includes:

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]

Use additional code:

code from category T31 or T32 to identify extent of body surface involved

Related codes in T21

Frequently asked questions

What is ICD-10 code T21.5?

T21.5 is the ICD-10-CM code for corrosion of first degree of trunk, in the block T20-T25 (Burns and corrosions of external body surface, specified by site).

Is T21.5 a billable code?

No. T21.5 is a header code with more specific child codes; report one of the billable codes listed above.

What category does T21.5 belong to?

It belongs to category T21 – Burn and corrosion of trunk.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.