Though we have written about CPT modifiers several times in the past, these add-ons continue to pose a puzzle to coders across many disciplines. After all, some sets of modifiers have similar definitions, meaning that choosing which one to use can be quite the conundrum. Such is the case for modifier 52 (Reduced services) and modifier 53 (Discontinued services), two modifiers with similar definitions that nonetheless have very different applications.

While coders use both 52 and 53 when a procedure is cut short, the reasonings behind the change of plans are different. Modifier 52 should be used when the provider expects ahead of time that the service will be reduced; in other words, the scope of the procedure is lessened because of the physician’s or patient’s choice. One of the most common ways coders use this modifier is for procedures that are typically bilateral (such as tonsillectomies), but have been reduced to unilateral voluntarily.

On the other hand, modifier 53 applies when the overall procedure must be discontinued because of extenuating circumstances. As the word “discontinued” implies, modifier 53 is only applicable once the procedure has begun in full, such as after anesthesia has been administered. In contrast to modifier 52, modifier 53 should only be used when the issue that arises is unforeseen and poses a risk to the health of the patient. Additionally, it is important to note that modifier 53 does NOT apply when an endoscopic or laparoscopic procedure must change to an open procedure.

As with all modifiers, make sure that the documentation supports your selection. If the notes are unclear and you are unsure of whether the procedure is incomplete due to risk or to choice, be sure to query the provider accordingly. In addition, make sure to review the full list of CPT modifiers regularly so that you always have the information fresh in your mind.