New Patients And Old Patients – Medical Billing Differences There is a lot of confusion in many physician’s offices on how to handle the coding & medical billing of services rendered to an old patient and a new patient. New patient medical billing requires a lot more work than an established patient and this is reflected in the new coding requirements as well as reimbursement for your medical billing. One key to differentiating between new and established patients is understanding two terms used in CPT’s definition of a new patient: “professional services” and “group practice” and the understanding that Medicare’s definition of a new patient is slightly different than CPT’s. …