There can be many factors affecting the correct assignment of APCs. APC audits are similar to DRG validations in that the audit includes a thorough review and recoding of the medical records ensuring coding accuracy as well as the reasonableness of services rendered.

However, unlike DRGs, there can be multiple APCs on a single claim and there can be many factors affecting the correct assignment of APCs.

Other factors that can affect the assignment of the APCs are CCI violations, correct usage of modifiers, as well as current knowledge and expertise with all of the rules pertaining to pass-through items.

Lastly, the service must be deemed appropriate for the treatment of the diagnosis, which is determined by Local Coverage Determinations (LCDs) and Local Medical Review Policies (LMRPs).