What Is Hcpcs Code A0427?

What Is Hcpcs Code A0427? HCPCS code A0427 for Ambulance service, advanced life support, emergency transport, level 1 (ALS 1-emergency) as maintained by CMS falls under Ambulance and Other Transport Services and Supplies. How do I bill A0425? When billing HCPCS codes A0425, the number of loaded mileage is required in the service unit field