In simple words: This code is used for Medicaid patients who need an ambulance to take them to a medical facility in another state. The code covers the miles driven outside of the patient's home state.Medicare usually doesn't pay for this, and Medicaid rules differ by state. Usually, Medicaid only pays for ambulance rides to the closest place that can provide the needed medical care.

This code reports mileage for out-of-state ambulance transport for Medicaid patients.The provider reports the mileage outside the originating state on a per-mile basis. Note: Medicare generally doesn't cover this service. Medicaid coverage varies by state but usually covers transport to the nearest appropriate facility for necessary diagnostic or therapeutic services. This is limited to the payment equivalent of bringing the service to the patient.Appropriate facilities can include hospitals, critical access hospitals, skilled nursing facilities, dialysis centers, or the patient's home.State Medicaid programs might offer non-emergency transport for other covered services.

Example 1: A Medicaid patient in New York needs transport to a specialized hospital in Pennsylvania. The ambulance provider would use A0021 to bill the mileage driven in Pennsylvania., A Medicaid patient requires transport to a dialysis center located across state lines. The portion of the ambulance trip that occurs out of state is billed using A0021., A Medicaid patient in a rural area near a state border is transported to the nearest hospital, which happens to be across the state line. Code A0021 is used to bill the out-of-state mileage.

Documentation should include the patient's Medicaid eligibility, the origin and destination of the transport, and a detailed record of mileage driven within and outside the state.

** Secondary insurers may require Medicare denial for services excluded by Medicare. Submit to Medicare with GY modifier for statutorily excluded services to generate a denial for the secondary insurer.