Of all the modifiers that exist in the world of CPT codes, modifier 59 is one of the trickiest. Succinctly described as the modifier for a “distinct procedural service,” 59 may seem simple, but it is actually the single most frequently misused modifier. Thankfully, there are a few basic tips and tricks that can help you make the most of this misunderstood number.

In essence, modifier 59 is designed to differentiate between multiple procedures that were performed during the same visit, but to different areas of the body. For example, a correct usage of this modifier would be to code for a session in which a physical therapist treated a patient using both therapeutic activity (code 97530) and manual therapy (code 97140). Keep in mind, however, that in this example, there would need to be a distinct separation between the two procedures in order to use modifier 59; performing both types of therapy at the same time disqualifies them from using the modifier.

On that note, one of the biggest misuses of modifier 59 is to divide up procedures on a claim so that they can all be billed separately. This abuse of the modifier can result in an audit, as separating the procedures will often charge the insurer far more than bundling them. It is also important to remember that modifier 59 cannot be used if there is another modifier that would be more appropriate. If you have any doubt, be sure to check a modifier list before coding.

It is also worth mentioning that medical billers should not be the ones to add this modifier. Affixing modifier 59 is the responsibility of the coder or the provider. If you as a coder believe that the documentation supports the use of this modifier even though it is not included on the patient’s chart, be sure to query the physician to confirm that it should be added to the corresponding codes.