What type of procedures do "Modifier" codes supplement in CPT coding?

Modifier codes in CPT coding serve to provide additional information about the service performed. They are used to clarify circumstances surrounding a procedure, such as whether the service was altered in any way but not changed in its definition or code. Modifiers can indicate various situations, such as multiple procedures performed, services that were bilateral, staged or related procedures, and those that were increased or decreased in intensity.

By applying modifiers, healthcare providers ensure that the documentation accurately reflects the specific nuances of the service, ensuring proper billing and reimbursement. This detailed coding is essential in communicating the full context of the service or procedure provided to the patient, enabling insurers to process claims accurately based on the intricacies involved.

In contrast, while diagnostic procedures, outpatient procedures, and surgical procedures can involve the use of modifiers, they are not the primary focus of what modifiers actually do. Instead, modifiers apply broadly to various services, making option D the most comprehensive answer regarding the role of modifier codes in CPT coding.