North Carolina Subscriber
Answer: The correct code for a standby service is 99360 (Physician standby service, requiring prolonged physician attendance, each 30 minutes [e.g., operative standby, standby for frozen section, for cesarean/high-risk delivery, for monitoring EEG]). Medicare never pays for this service, but some private carriers might.
Code 99360 specifies "physician," but you might be able to report this code for a CRNA, depending on the carrier. If the CRNA spent more than 30 minutes on standby and did not provide care or services to anyone else during the time (which is what the code requires), call the carrier to see if the time is billable. Most carriers probably won't cover it, but you can always ask.