Is L21 a billable ICD-10-CM code?

No. L21 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does L21 sit in the tabular list?

Diseases of the skin and subcutaneous tissue (L00-L99), in the block Dermatitis and eczema (L20-L30).

L21

L21 — Seborrheic dermatitis

Non-billable headerICD-10-CM

L21 is a non-billable header ICD-10-CM code for seborrheic dermatitis. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes2 — not included here, but may coexist

The excluded condition is not part of this code, but a patient can have both. You may code both.

infective dermatitis (L30.3)
seborrheic keratosis (L82.-)

Risk adjustment

L21 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 L21

4 child codes. Green means billable.

Questions about L21

Is L21 a billable ICD-10-CM code?: No. L21 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does L21 sit in the tabular list?: Diseases of the skin and subcutaneous tissue (L00-L99), in the block Dermatitis and eczema (L20-L30).