Can someone explain to me when you would attach modifier 52 to CPT codes 93653 and 93656 (EPS study) when there are missing components in the operative note? I am told that you can only use this modifier if the procedure is without anesthesia. Those documents are out dated. The recent documents does not support "without anesthesia." My CPT Expert book, under these codes, list modifiers that can be used. It includes modifier 52.