Part B Medicare Administrative Contractor (MAC) File Explanation

The Four Files

The first three files are to be used for services provided to beneficiaries in a Part A covered Skilled Nursing Facility (SNF) stay. Codes that can be separately billed to the Part B MAC by physicians, non-physician practitioners, and suppliers (other than ambulance suppliers) are found in Files 1 and 2. If the code is not found in either of these two files, the service is subject to SNF consolidated billing and the physician, non-physician practitioner, or supplier must look to the SNF for payment of the service. The MAC will not pay the service.

File 3 is just for ambulance services. The codes on this file, when submitted with the NN origin/destination modifier, (i.e., transport between 2 SNFs), are subject to consolidated billing and the supplier must look to the SNF for payment of the service. The Part B MAC will not pay the service. The services are separately payable by the MAC when submitted with any other origin/destination modifier.

File 4 is only to be used for services rendered to beneficiaries in a Part B non-covered stay. It includes the therapy codes that are subject to SNF consolidated billing for beneficiaries in a Part B non-covered SNF stay. The physician, non-physician practitioner, or supplier must look to the SNF for payment of these services. The Part B MAC will not pay these services.

How To Move Around the Files:

Click on Search Instructions (see Downloads below) to search PDF files. You will be given instructions on how to move around the code files. In Excel files, select "Control key (Ctrl) + F" key and enter code.  Select "Find All."

Updating the Files:

Periodically, the files will be updated to correct errors and to include newly developed procedure and supply codes. An explanation of the latest update will be included below under each file name.