Medicare works somewhat like an HMO. Medicine prescriptions provided by will be covered, as will some limited laboratory tests and x-rays. For those patients who have primary insurance apart from Medicare, then office visit bills will be paid by these companies when you submit a claim. For most other Medicare patients, physician fees and office visits will need to be paid out of pocket. The services of Medicare-assigned doctors will thus be less expensive. But can provide many medical services not covered by Medicare (such as routine physical exams), and when it comes to convenience, access, and time savings, is still a great pick.