Question: Some of the coders in the office were discussing a news story in which a patient sued a surgeon for performing the wrong surgery. If that were to happen at our practice, how would we code the encounter? Maine Subscriber Answer: Perhaps surprisingly, there is a modifier for these unfortunate situations. When your provider performs the wrong procedure on a patient, you'll use modifier PC (Wrong surgery or other invasive procedure on a patient) on the claim. Medicare (and payers that follow Medicare rules) will want you to use this modifier for informational purposes only. Example: A patient reports to the practice for a planned screening colonoscopy, but the gastroenterologist performs an esophageal motility study instead. On the claim, you'd report 91010 (Esophageal motility [manometric study of the esophagus and/or gastroesophageal junction] study with interpretation and report) for the study with modifier PC appended. Result: When you submit codes with the modifier PC attached, Medicare will deny the claim. You should, however, report this modifier to tell the payer that you made a surgical mistake. If another provider performs a different surgery, that might be reimbursed depending on the circumstances and the documentation around it. Unfortunately, some practices are erroneously assigning modifier PC to reflect the professional component of a service, which they should actually be reporting with modifier 26 (Professional component).