Question: One of our providers excised a malignant lesion on the patient’s forearm under general anesthesia. We cannot find a code to bill the MAC anesthesia under. Do you have any advice on this? Alabama Subscriber Answer: The lesion excision crosses to anesthesia code 00400 (Anesthesia for procedures on the integumentary system on the extremities, anterior trunk and perineum; not otherwise specified). Because the patient had MAC anesthesia, you should bill 00400 with the G8 modifier (Monitored anesthesia care (mac) for deep complex, complicated, or markedly invasive surgical procedure).