Is S90 a billable ICD-10-CM code?

No. S90 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does S90 sit in the tabular list?

Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Injuries to the ankle and foot (S90-S99).

S90

S90 — Superficial injury of ankle, foot and toes

Non-billable headerICD-10-CM

S90 is a non-billable header ICD-10-CM code for superficial injury of ankle, foot and toes. 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 S90

A: initial encounter
D: subsequent encounter
S: sequela

Other codes that can never be billed with S90

These codes carry an Excludes1 note pointing at S90. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading S90 alone.

S91.05Open bite of ankle
S91.15Open bite of toe without damage to nail
S91.25Open bite of toe with damage to nail
S91.35Open bite of foot

Risk adjustment

S90 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 S90

8 child codes. Green means billable.

Questions about S90

Is S90 a billable ICD-10-CM code?: No. S90 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does S90 sit in the tabular list?: Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Injuries to the ankle and foot (S90-S99).