Health plans have provider networks. Patients can see in-network doctors and facilities without added out-of-network charges. Out-of-network providers and facilities don’t have in-network contracts with your insurer. That means you’ll have to pay more or even all of the health care costs. Out-of-network medical bills are a common reason for surprise billing. Surprise billing is when you get an unexpected massive medical bill. That’s often caused by getting care from an out-of-network provider or hospital. This is especially common in emergency rooms.