ICD-10 Code for Corrosion

Also indexed as (injury) (acid) (caustic) (chemical) (lime) (external) (internal)

The ICD-10-CM code for corrosion is T30.4 — Corrosion of unspecified body region, unspecified degree. This is the code the Alphabetic Index gives for corrosion with no further qualifier, valid for FY2027 (October 1, 2026 – September 30, 2027).

BillableUnspecified

T30.4 is billable but unspecified. If the documentation names a type, site or cause, one of the more specific codes below is likely expected.

Which corrosion code should you use?

The Alphabetic Index lists 448 codes under Corrosion. Which one applies depends on the qualifier documented in the record — the type, site, cause, or associated condition. Find the qualifier below, then verify the code in the Tabular List before using it.

By type

abdomen, abdominal	T21.42Not billable	Corrosion of unspecified degree of abdominal wall
above elbow	T22.439Not billable	Corrosion of unspecified degree of unspecified upper arm
alimentary tract NEC	T28.7Not billable	Corrosion of other parts of alimentary tract
ankle	T25.419Not billable	Corrosion of unspecified degree of unspecified ankle
axilla	T22.449Not billable	Corrosion of unspecified degree of unspecified axilla
back	T21.44Not billable	Corrosion of unspecified degree of lower back
buttock	T21.45Not billable	Corrosion of unspecified degree of buttock
calf	T24.439Not billable	Corrosion of unspecified degree of unspecified lower leg
cervix	T28.8Not billable	Corrosion of internal genitourinary organs
cheek	T20.46Not billable	Corrosion of unspecified degree of forehead and cheek
chest wall	T21.41Not billable	Corrosion of unspecified degree of chest wall
chin	T20.43Not billable	Corrosion of unspecified degree of chin
colon	T28.7Not billable	Corrosion of other parts of alimentary tract
cornea	T26.6Not billable	Corrosion of cornea and conjunctival sac
dorsum of hand	T23.469Not billable	Corrosion of unspecified degree of back of unspecified hand
ear	T20.41Not billable	Corrosion of unspecified degree of ear [any part, except ear drum]
elbow	T22.429Not billable	Corrosion of unspecified degree of unspecified elbow
epiglottis	T27.4Not billable	Corrosion of larynx and trachea
esophagus	T28.6Not billable	Corrosion of esophagus
eye and adnexa	T26.9Not billable	Corrosion of eye and adnexa, part unspecified
eyelid	T26.5Not billable	Corrosion of eyelid and periocular area
finger	T23.429Not billable	Corrosion of unspecified degree of unspecified single finger (nail) except thumb
foot	T25.429Not billable	Corrosion of unspecified degree of unspecified foot
forearm	T22.419Not billable	Corrosion of unspecified degree of unspecified forearm
forehead	T20.46Not billable	Corrosion of unspecified degree of forehead and cheek
gastrointestinal tract NEC	T28.7Not billable	Corrosion of other parts of alimentary tract
hand	T23.409Not billable	Corrosion of unspecified degree of unspecified hand, unspecified site
head	T20.40Not billable	Corrosion of unspecified degree of head, face, and neck, unspecified site
internal organ	T28.90Not billable	Corrosions of unspecified internal organs
intestine	T28.7Not billable	Corrosion of other parts of alimentary tract
knee	T24.429Not billable	Corrosion of unspecified degree of unspecified knee
larynx	T27.4Not billable	Corrosion of larynx and trachea
lip	T20.42Not billable	Corrosion of unspecified degree of lip(s)
lung	T27.5Not billable	Corrosion involving larynx and trachea with lung
mouth	T28.5Not billable	Corrosion of mouth and pharynx
neck	T20.47Not billable	Corrosion of unspecified degree of neck
nose	T20.44Not billable	Corrosion of unspecified degree of nose (septum)
palm	T23.459Not billable	Corrosion of unspecified degree of unspecified palm
pharynx	T28.5Not billable	Corrosion of mouth and pharynx
rectum	T28.7Not billable	Corrosion of other parts of alimentary tract
respiratory tract	T27.7Not billable	Corrosion of respiratory tract, part unspecified
scalp	T20.45Not billable	Corrosion of unspecified degree of scalp [any part]
scapular region	T22.469Not billable	Corrosion of unspecified degree of unspecified scapular region
shoulder	T22.459Not billable	Corrosion of unspecified degree of unspecified shoulder
stomach	T28.7Not billable	Corrosion of other parts of alimentary tract
thigh	T24.419Not billable	Corrosion of unspecified degree of unspecified thigh
throat	T28.5Not billable	Corrosion of mouth and pharynx
thumb	T23.419Not billable	Corrosion of unspecified degree of unspecified thumb (nail)
toe	T25.439Not billable	Corrosion of unspecified degree of unspecified toe(s) (nail)
tongue	T28.5Not billable	Corrosion of mouth and pharynx
tonsil	T28.5Not billable	Corrosion of mouth and pharynx
trachea	T27.4Not billable	Corrosion of larynx and trachea
trunk	T21.40Not billable	Corrosion of unspecified degree of trunk, unspecified site
upper limb	T22.40Not billable	Corrosion of unspecified degree of shoulder and upper limb, except wrist and hand, unspecified site
uterus	T28.8Not billable	Corrosion of internal genitourinary organs
vagina	T28.8Not billable	Corrosion of internal genitourinary organs
wrist	T23.479Not billable	Corrosion of unspecified degree of unspecified wrist

Corrosion abdomen, abdominal

first degree	T21.52Not billable	Corrosion of first degree of abdominal wall
second degree	T21.62Not billable	Corrosion of second degree of abdominal wall
third degree	T21.72Not billable	Corrosion of third degree of abdominal wall

Corrosion above elbow

first degree	T22.539Not billable	Corrosion of first degree of unspecified upper arm
left	T22.432Not billable	Corrosion of unspecified degree of left upper arm
right	T22.431Not billable	Corrosion of unspecified degree of right upper arm
second degree	T22.639Not billable	Corrosion of second degree of unspecified upper arm
third degree	T22.739Not billable	Corrosion of third degree of unspecified upper arm

Corrosion ankle

first degree	T25.519Not billable	Corrosion of first degree of unspecified ankle
left	T25.412Not billable	Corrosion of unspecified degree of left ankle
right	T25.411Not billable	Corrosion of unspecified degree of right ankle
second degree	T25.619Not billable	Corrosion of second degree of unspecified ankle
third degree	T25.719Not billable	Corrosion of third degree of unspecified ankle

Corrosion axilla

first degree	T22.549Not billable	Corrosion of first degree of unspecified axilla
left	T22.442Not billable	Corrosion of unspecified degree of left axilla
right	T22.441Not billable	Corrosion of unspecified degree of right axilla
second degree	T22.649Not billable	Corrosion of second degree of unspecified axilla
third degree	T22.749Not billable	Corrosion of third degree of unspecified axilla

Corrosion back

first degree	T21.54Not billable	Corrosion of first degree of lower back
second degree	T21.64Not billable	Corrosion of second degree of lower back
third degree	T21.74Not billable	Corrosion of third degree of lower back
upper	T21.43Not billable	Corrosion of unspecified degree of upper back

Corrosion buttock

first degree	T21.55Not billable	Corrosion of first degree of buttock
second degree	T21.65Not billable	Corrosion of second degree of buttock
third degree	T21.75Not billable	Corrosion of third degree of buttock

Corrosion calf

first degree	T24.539Not billable	Corrosion of first degree of unspecified lower leg
left	T24.432Not billable	Corrosion of unspecified degree of left lower leg
right	T24.431Not billable	Corrosion of unspecified degree of right lower leg
second degree	T24.639Not billable	Corrosion of second degree of unspecified lower leg
third degree	T24.739Not billable	Corrosion of third degree of unspecified lower leg

Corrosion cheek

first degree	T20.56Not billable	Corrosion of first degree of forehead and cheek
second degree	T20.66Not billable	Corrosion of second degree of forehead and cheek
third degree	T20.76Not billable	Corrosion of third degree of forehead and cheek

Corrosion chest wall

first degree	T21.51Not billable	Corrosion of first degree of chest wall
second degree	T21.61Not billable	Corrosion of second degree of chest wall
third degree	T21.71Not billable	Corrosion of third degree of chest wall

Corrosion chin

first degree	T20.53Not billable	Corrosion of first degree of chin
second degree	T20.63Not billable	Corrosion of second degree of chin
third degree	T20.73Not billable	Corrosion of third degree of chin

Corrosion dorsum of hand

first degree	T23.569Not billable	Corrosion of first degree of back of unspecified hand
left	T23.462Not billable	Corrosion of unspecified degree of back of left hand
right	T23.461Not billable	Corrosion of unspecified degree of back of right hand
second degree	T23.669Not billable	Corrosion of second degree back of unspecified hand
third degree	T23.769Not billable	Corrosion of third degree back of unspecified hand

Corrosion ear

drum	T28.91Not billable	Corrosions of ear drum
first degree	T20.51Not billable	Corrosion of first degree of ear [any part, except ear drum]
second degree	T20.61Not billable	Corrosion of second degree of ear [any part, except ear drum]
third degree	T20.71Not billable	Corrosion of third degree of ear [any part, except ear drum]

Corrosion elbow

first degree	T22.529Not billable	Corrosion of first degree of unspecified elbow
left	T22.422Not billable	Corrosion of unspecified degree of left elbow
right	T22.421Not billable	Corrosion of unspecified degree of right elbow
second degree	T22.629Not billable	Corrosion of second degree of unspecified elbow
third degree	T22.729Not billable	Corrosion of third degree of unspecified elbow

Corrosion extent

less than 10 percent	T32.0	Corrosions involving less than 10% of body surface
10-19 percent	T32.10	Corrosions involving 10-19% of body surface with 0% to 9% third degree corrosion
20-29 percent	T32.20	Corrosions involving 20-29% of body surface with 0% to 9% third degree corrosion
30-39 percent	T32.30	Corrosions involving 30-39% of body surface with 0% to 9% third degree corrosion
40-49 percent	T32.40	Corrosions involving 40-49% of body surface with 0% to 9% third degree corrosion
50-59 percent	T32.50	Corrosions involving 50-59% of body surface with 0% to 9% third degree corrosion
60-69 percent	T32.60	Corrosions involving 60-69% of body surface with 0% to 9% third degree corrosion
70-79 percent	T32.70	Corrosions involving 70-79% of body surface with 0% to 9% third degree corrosion
80-89 percent	T32.80	Corrosions involving 80-89% of body surface with 0% to 9% third degree corrosion
90 percent or more	T32.90	Corrosions involving 90% or more of body surface with 0% to 9% third degree corrosion

Index terms and codes are reproduced from the official ICD-10-CM FY2027 release. The Alphabetic Index is a finding aid — a code must always be verified in the Tabular List before it is reported. Data sources