Question: One of the coders in our department insists that we can use modifier 59 if the surgeon performs a "separate procedure" for a diagnosis different from the diagnosis that prompted the primary procedure. In looking over Medicare and CPT guidelines, however, I see nothing to support this. Is a separate diagnosis enough to warrant modifier 59? Maine Subscriber Answer: According to CPT instructions and Chapter 1 of the national Correct Coding Initiative (CCI), you may append modifier 59 (Distinct procedural service) when the physician: • sees a patient during a different session • treats a different site or organ system • makes a separate incision/excision • tends to a different lesion • treats a separate injury. Although the diagnosis that prompts the follow-up procedure with modifier 59 may be different from the diagnosis that prompted the primary procedure, a different diagnosis by itself does not justify using modifier 59. Bottom line: Append modifier 59 to a claim only if you are certain of the involved procedures' distinct nature (regardless of the diagnoses) and never simply to override CCI bundles and get paid.