ICD-10-CM 2027 diagnosis code

T25.491Corrosion of unspecified degree of multiple sites of right ankle and foot

Not billable — use a more specific codeRequires 7th character

T25.491 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it and add the required 7th character.Short description: Corrosion of unsp deg mult sites of right ankle and foot

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 T25.491

T25.491 is the ICD-10-CM diagnosis code for corrosion of unspecified degree of multiple sites of right ankle and foot. It belongs to category T25 (burn and corrosion of ankle and foot), 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 3 subcodes must be used instead.

Within T25.49 (corrosion of unspecified degree of multiple sites of ankle and foot), T25.491 is specifically for corrosion of unspecified degree of multiple sites of right ankle and foot. Related codes cover left ankle and foot (T25.492) and unspecified ankle and foot (T25.499).

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.

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 T25

Ainitial encounterT25.491A
Dsubsequent encounterT25.491D
SsequelaT25.491S

Notes that apply from higher levels

Instructions written at a parent level also apply to T25.491.

› From T25.4 Corrosion of unspecified degree of ankle and foot

Code first

(T51-T65) to identify chemical and intent

Use additional code

external cause code to identify place (Y92)

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.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to T25.491.

Corrosion (injury) (acid) (caustic) (chemical) (lime) (external) (internal) › lower › limb › multiple sites, except ankle and foot › ankle and foot › right

Code history

2016
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2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about T25.491

Is T25.491 billable?: No. T25.491 is a header code. Report one of its more specific subcodes instead.