If you have three medical insurances are doctors required to bill them all before billing the patient?

You doctor is not obligated to send the bill to ANY insurance company unless the agreement between the carrier and the doctor requires it. More and more doctors are trying to relieve themselves of the paperwork nightmare of dealing with insurance companies. They will accept the negotiated rate but demad it at the time of service from the patient. It is then the problem for the patient to collect from the carrier.