When is it appropriate to use an "add-on" code in CPT?

Using an "add-on" code in the Current Procedural Terminology (CPT) system is appropriate when a procedure is performed in conjunction with another primary procedure. Add-on codes are specifically designed to provide additional information about procedures that are performed at the same time as a primary procedure. They indicate that the service is over and above the primary service, enhancing the overall understanding of the care delivered.

These codes are particularly useful in scenarios where certain procedures can't be adequately captured with the primary procedure code alone, allowing for more precise documentation of the medical services that were rendered. This ensures that the payer has a clear understanding of the full scope of care provided, which is essential for accurate reimbursement and proper clinical reporting. Therefore, the use of an add-on code signals to insurers and healthcare providers that there was an additional, related procedure that should be recognized in conjunction with the primary treatment.