Is S21.451 a billable ICD-10-CM code?

No. S21.451 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does S21.451 sit in the tabular list?

Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Injuries to the thorax (S20-S29).

What cannot be coded together with S21.451?

S21.451 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above S21.451 (S21.45, S21) and apply to it just the same.

S21.451

S21.451 — Open bite of right back wall of thorax with penetration into thoracic cavity

Non-billable headerICD-10-CMright

S21.451 is a non-billable header ICD-10-CM code for open bite of right back wall of thorax with penetration into thoracic cavity. It cannot be billed on its own: choose one of the more specific child codes below. This code also requires a 7th character before it is complete.

This code requires a 7th character

The appropriate 7th character is to be added to each code from category S21

A: initial encounter
D: subsequent encounter
S: sequela

Excludes1 inherited from the categories above S21.451

These are not written on S21.451, but they bind it: a note on a category applies to every code beneath it. Billing S21.451 with anything listed here is a denial.

Written on S21.45 — Open bite of back wall of thorax with penetration into thoracic cavity

superficial bite of back wall of thorax (S20.47)

Written on S21 — Open wound of thorax

traumatic amputation (partial) of thorax (S28.1)

Risk adjustment

S21.451 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code history

S21.451 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Code to one of these instead S21.451

3 child codes. Green means billable.

Related codes at this level

Codes that share S21.45. If S21.451 is not quite right, the correct code is usually one of these.

Questions about S21.451

Is S21.451 a billable ICD-10-CM code?: No. S21.451 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does S21.451 sit in the tabular list?: Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Injuries to the thorax (S20-S29).
What cannot be coded together with S21.451?: S21.451 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above S21.451 (S21.45, S21) and apply to it just the same.