Question: An EEG was performed on a patient under general anesthesia due to behavioral issues and autism. The EEG was ordered to evaluate her for seizures. What is the best anesthesia code to report? Maine Subscriber Answer: The current CPT® manual does not include a code specific to anesthesia in this situation. Your best option is to report 01999 (Unlisted anesthesia procedure(s)) and append modifier 23 (Unusual anesthesia). Most patients do not require anesthesia during an EEG, so also include documentation supporting the reason for anesthesia during the test.