Medicare Part B is your health insurance coverage. It covers two types of services, including medically necessary services to treat illnesses or conditions, such as doctor’s office visits, lab work, x-rays, and outpatient surgeries, and preventive services to keep you healthy, like cancer screenings and flu shots. Part B also covers medically necessary durable medical equipment such as wheelchairs and walkers to treat a disease or condition. Costs for Part B services vary, but frequently, you will pay a deductible and then 20% of the Medicare-approved amount, as long as you use providers who accept Medicare assignment.