What is the primary function of CPT modifiers?

The primary function of CPT modifiers is to describe alterations in standard procedures. Modifiers are two-digit codes appended to a primary CPT code to provide additional information about the service or procedure performed. They can indicate various factors, such as whether a procedure was altered in some way, whether multiple procedures were performed, or whether a procedure was performed on a specific site. This added information allows for a more precise billing and coding process, reflecting the nuances of the services provided to patients.

The other choices focus on aspects that are not the primary purpose of modifiers. For example, indicating the complexity of a code or classifying codes based on service type are not functions served by modifiers. Additionally, while there are annual updates to the coding guidelines and codes themselves, modifiers do not provide these updates but rather remain as tools to refine and clarify the billing of current codes.