Modifier XS: Separate structure — distinct service on a different organ or structure

Modifier Code

Code Type

Billing modifier

When to Use Modifier XS

Apply modifier XS when two services are performed on separate anatomical structures or organ systems during the same visit and require individual identification on the claim. In behavioral health, this may be relevant when a therapist also performs a discrete health or wellness assessment targeting a different body system. Confirm payer acceptance before applying XS to behavioral health claims.

CPT Codes Commonly Paired with Modifier XS

These CPT codes are frequently billed alongside modifier XS in therapy practice:

CPT 90837 - Psychotherapy, 60 minutes CPT 96130 - Psychological testing evaluation, first hour CPT 96131 - Psychological testing evaluation, each additional hour CPT 90791 - Psychiatric diagnostic evaluation

Superbill Notes for Modifier XS

What to include: Clearly document the distinct clinical rationale for each service on the superbill and identify the separate structures or systems addressed. Attach clinical notes that support the medical necessity of both services.

Adding Modifier XS to a Superbill

Superbilled lets you add modifier codes directly to each line item on your superbill. When generating a superbill with modifier XS, make sure to include your NPI number, the patient's diagnosis code, date of service, fee charged, and amount paid. The modifier appears alongside the CPT code on the claim.

Generate a superbill with Modifier XS free