Physician Assistant's billing

How to claims for physician assistants. New patients and follow ups. Is there a modifier?

re: Physician Assistant's billing

Our PAs/NPs are credentialed with Medicare, Medicaid, BC and United. We bill under their name (no mods) with these carriers and as incident-to or under the supervising physician for the other carriers. Only in surgery do we add an -AS modofier (non-physician assist) to the appropriate procedures.