Phototherapy for conditions like psoriasis, vitiligo, or eczema requires precise billing. Payers are strict about session limits, documentation of medical necessity, and the use of the correct CPT code (UVB vs. PUVA). Simple errors can lead to months of denied claims.

Common Phototherapy Codes

CPT 96900 (Actinotherapy):

• This code is for unsupervised UVB treatment or treatment to a localized area (e.g., excimer laser).
• It is billed per session.

CPT 96910 (UVB Therapy):

• This is the most common code, for supervised phototherapy (tar and/or UVB) for the entire body.
• Used for "light box" treatments for psoriasis.

CPT 96912 (PUVA Therapy):

• This code is for psoralens and ultraviolet A (PUVA) treatment.
• It has a higher reimbursement but requires documentation of the psoralen administration.

Billing Rules and Requirements

• Bill Per Session: Phototherapy codes are "per session" codes. You can only bill one unit, per day, regardless of the time spent.
• Medical Necessity: Your notes must clearly state the diagnosis (e.g., Psoriasis L40.0) and why phototherapy is required (e.g., "failed topical steroids," "severe BSA involvement").
• E/M Visits: You cannot bill an E/M visit (e.g., 99212) at every phototherapy session. The "check-in" is bundled.
• Modifier 25: An E/M is only billable if the provider performs a significant, separate evaluation (e.g., monthly check-up for drug management) and appends Modifier 25.

The "Per Session" Audit Risk