What term describes the codes that provide additional information about a service that is not fully captured by a five-digit CPT code?

The term that describes the codes providing additional information about a service not fully captured by a five-digit CPT code is "Modifiers." Modifiers are essential tools in coding as they add specificity to the procedure being reported. They indicate that a service or procedure has been altered by certain circumstances but has not changed in its definition or code.

Modifiers can convey information about the location of a service, whether the service was bilateral, or if multiple procedures were performed, among other details. This added information is crucial for accurate billing and sufficient communication between healthcare providers and payers, ensuring that the services rendered are understood fully.

In contrast, the other terms do not accurately describe this function within the CPT coding system. Subcodes, alterations, and descriptors do not have the same specific role as modifiers in enhancing or clarifying the information captured by the primary CPT codes. Thus, modifiers are recognized as the correct answer in providing the necessary details that go beyond the primary coding.