Is S21.059A a billable ICD-10-CM code?

Yes. S21.059A is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does S21.059A 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 S21.059A?

S21.059A 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 S21.059A (S21.05, S21) and apply to it just the same.

S21.059A

S21.059A — Open bite of unspecified breast, initial encounter

Billable / specific codeICD-10-CMunspecified

S21.059A is a billable, specific ICD-10-CM code for open bite of unspecified breast, initial encounter. It is valid for submission on a claim.

7th character "A" — initial encounter

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 S21.059A

These are not written on S21.059A, but they bind it: a note on a category applies to every code beneath it. Billing S21.059A with anything listed here is a denial.

Written on S21.05 — Open bite of breast

superficial bite of breast (S20.17)

Written on S21 — Open wound of thorax

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

Risk adjustment

S21.059A 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

S21.059A has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share S21.059. If S21.059A is not quite right, the correct code is usually one of these.

Questions about S21.059A

Is S21.059A a billable ICD-10-CM code?: Yes. S21.059A is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does S21.059A 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 S21.059A?: S21.059A 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 S21.059A (S21.05, S21) and apply to it just the same.