Which coding error occurs when two procedures that can be billed as one are coded separately?

Unbundling refers to the practice of coding two or more procedures separately when they should be billed together as a single comprehensive service. This happens when a provider opts to break down a procedure into individual components rather than using a specific bundled code that encompasses all of those services. Unbundling can lead to increased costs for the patient and skewed data for healthcare reimbursement, as the proper billing methodology encourages the use of bundled codes to reflect the entirety of the services rendered efficiently.

In contrast, downcoding involves using a lower-level code than is appropriate for the services provided; grouping pertains to the combination of services under a single code, which is typically the goal to avoid unbundling; and overcoding means coding services at a higher level than warranted, which can also lead to penalties or audits. Hence, unbundling is identified as the error associated with the separate coding of procedures that should be combined.