In ABA therapy, CPT codes 97153 and 97155 differ primarily in the type of service provided and the professional responsible for delivering that service:

• 97153 (Direct Treatment): This code is used for one-on-one therapy sessions where a Registered Behavior Technician (RBT) implements the treatment protocol designed by a BCBA. It focuses on the direct delivery of skill-building or behavior-reduction goals.
• 97155 (Protocol Modification): This code is used when a Board Certified Behavior Analyst (BCBA) is present during a session to oversee and modify the treatment plan. It accounts for clinical supervision and real-time adjustments to the protocol based on the child’s progress, rather than just direct implementation.

Key billing similarities and requirements include:

1. Unit Increments: Both services are billed in 15-minute units. Providers must follow the “8-minute rule,” where at least 8 minutes of a block must be completed to bill for one unit.
2. Medical Necessity: Both codes require documentation showing that the services are medically necessary for the child’s treatment.
3. Separation of Services: Minutes from these different codes cannot be combined; they must be tracked and calculated separately. Billing both on the same day without clearly documenting separate, distinct services can lead to claim denials.

• ABA Therapy CPT Codes: Complete Guide for Providers