Which modifier would be used to characterize a transactional procedure?

The modifier that characterizes a transactional procedure is -T1. In the context of Current Procedural Terminology (CPT), the -T modifiers are specifically designed to indicate various types of transactions related to a primary procedure or service. The -T1 modifier signals that the procedure or service is part of a transactional approach, which can involve procedures that are both facilitating and addressing specific transactional components in a patient care context.

The other choices do not relate directly to transactional procedures. For instance, -4A isn’t a recognized modifier within the CPT system pertaining to transactional characterizations. The -P5 modifier is used to indicate a patient’s physical status and may not relate specifically to procedural transactions. Similarly, -U is not associated with transactional procedures, leading to the conclusion that -T1 is indeed the appropriate choice for indicating a transactional procedure.