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ICD-10-CM 2027

ICD-10 code for sternal region blister

S20.329

Blister (nonthermal) of unspecified front wall of thorax

Header — needs a more specific code

From the official ICD-10-CM alphabetic index entry “Blister (nonthermal) › sternal region”. Page updated September 29, 2026.

About coding sternal region blister

The ICD-10-CM code for sternal region blister is S20.329 (Blister (nonthermal) of unspecified front wall of thorax).

Within S20.32, choose S20.329 (unspecified front wall of thorax) only when documentation doesn't support a more specific option: right front wall of thorax (S20.321), left front wall of thorax (S20.322), bilateral front wall of thorax (S20.323) and middle front wall of thorax (S20.324).

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.

Common questions about sternal region blister ICD-10 codes

What is the ICD-10 code for sternal region blister?

S20.329 — Blister (nonthermal) of unspecified front wall of thorax (a header code; report a more specific subcode).

Is S20.329 billable?

No. S20.329 is a header code. Report one of its more specific subcodes instead.