Perform of proc (op) on patient not scheduled for surgery

This code indicates that a surgical procedure was performed on a patient who was not originally scheduled for an operation. This typically signifies an unexpected or unplanned intervention, often due to an acute change in the patient's condition or an emergent finding during a different scheduled encounter.

Apply this code when a patient undergoes an operation that was not pre-booked, such as an emergency appendectomy performed during a hospital admission for abdominal pain, or an unexpected surgical intervention identified during a diagnostic procedure. It is used to capture the unplanned nature of the surgical event.

• Always assign a primary diagnosis code explaining the medical necessity for the unplanned procedure.
• This code is for external cause reporting and should be used as a secondary code.
• Distinguish from procedures that were scheduled but then performed at a different time or location; this code specifically addresses the unscheduled nature of the operation itself.