What indicates that a service is secondary to another procedure?

The indication that a service is secondary to another procedure is effectively represented by the use of Modifier -S. This modifier is specifically designed to indicate that a procedure was performed or a service provided that is not the primary procedure and is often used to show that the service is related but distinct from a primary procedure.

Using this modifier clarifies to the payer that while the procedure is related to another service performed, it is separate enough to warrant reimbursement or acknowledgment as a distinct service. This can be especially important in ensuring correct billing practices and ensuring that physicians are compensated for all services provided without them being unintentionally bundled or excluded from payment due to association with a primary procedure.

The other modifiers do not serve the same purpose as Modifier -S. For instance, Modifier -F8 and Modifier -G2 do not apply in this context and typically relate to different specific coding situations or billing circumstances. Modifier -79 is used to indicate that a procedure was performed during the postoperative period of another procedure and that it is unrelated to the surgical procedure; while this provides additional context, it does not reflect a secondary service in the same way as Modifier -S does. Thus, Modifier -S is appropriately the modifier that illustrates a service being secondary to another procedure.