For years as a Free Standing Facility when a patient is prepared for a Colonoscopy and the MD can’t advance the scope due to poor prep, we’ve always appended Modifier 52 (discontinued service). It is our understanding the patient will return the next day with additional prep to complete the procedure. I am reading the notes in the CPT book where it talks about incomplete colonoscopy. My interpretation of 73 and 74 modifier is when the procedure is discontinued due to extenuating circumstances or those that threaten the well being of the patient. Which modifier is correct for incomplete colon due to poor prep for the FACILITY 52, 73, or 74?

I would also need documentation to support.