Is S21.9 a billable ICD-10-CM code?

No. S21.9 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does S21.9 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).

S21.9

S21.9 — Open wound of unspecified part of thorax

Non-billable headerICD-10-CM

S21.9 is a non-billable header ICD-10-CM code for open wound of unspecified part of thorax. 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

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

Open wound of thoracic wall NOS

Other codes that can never be billed with S21.9

These codes carry an Excludes1 note pointing at S21.9. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading S21.9 alone.

S20.97Other superficial bite of unspecified parts of thorax
S20.97XAOther superficial bite of unspecified parts of thorax, initial encounter
S20.97XDOther superficial bite of unspecified parts of thorax, subsequent encounter
S20.97XSOther superficial bite of unspecified parts of thorax, sequela

Risk adjustment

S21.9 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 to one of these instead S21.9

6 child codes. Green means billable.

Related codes at this level

Codes that share S21. If S21.9 is not quite right, the correct code is usually one of these.

Questions about S21.9

Is S21.9 a billable ICD-10-CM code?: No. S21.9 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does S21.9 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).