What is CPT Code A0999-GY?

A0999 = Unlisted Ambulance Service. It is a HCPCS procedure code used by ambulance companies for billing miscellaneous supplies and services. GY modifier = "Item or service statutorily excluded or does not meet the definition of any Medicare benefit." A0999 is occasionally used to bill for late charges, interest, first responder, wait time and is usually not covered by insurance carriers because they are not considered medically necessary.