Is J21 a billable ICD-10-CM code?

No. J21 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does J21 sit in the tabular list?

Diseases of the respiratory system (J00-J99), in the block Other acute lower respiratory infections (J20-J22).

J21

J21 — Acute bronchiolitis

Non-billable headerICD-10-CM

J21 is a non-billable header ICD-10-CM code for acute bronchiolitis. 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.

respiratory bronchiolitis interstitial lung disease (J84.115)

Includes

Conditions this code covers.

acute bronchiolitis with bronchospasm

Other codes that can never be billed with J21

These codes carry an Excludes1 note pointing at J21. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading J21 alone.

B97.4Respiratory syncytial virus as the cause of diseases classified elsewhere
J98.01Acute bronchospasm

Risk adjustment

J21 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 J21

4 child codes. Green means billable.

Questions about J21

Is J21 a billable ICD-10-CM code?: No. J21 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does J21 sit in the tabular list?: Diseases of the respiratory system (J00-J99), in the block Other acute lower respiratory infections (J20-J22).