I am an RNFA. I finished my certification about a year ago. The course does little to prepare you for the business end of it. I assist for the doctor I work for as an office nurse. (Gynecologist). You need to start now and get an NPI and a Tax identification #. In my area RNFA's are not used as much, so the physicians have there office nurse trained to assist. You will need to contract with the physician. The non paying cases are just that non paying. You can bill the patient for the allowed amount, and they will hopefully pay. No I do not have a Medicare provider ID, they only credential advanced practice nurses with an RNFA