In general, Medicare coverage is biased against preventive medicine -- for example, the most basic preventive tool, the regular annual physical, isn't covered. But in recent years Part B has been expanding to include a number of preventive procedures.

Covered services include one initial routine physical (sometimes called an initial wellness exam) by a participant's own doctor when he or she first enrolls in Part B. Part B also covers a number of specific screening exams, though with certain restrictions -- required risk factors, for example, or limited test frequency. These exams include mammograms, pap smears and pelvic exams, colorectal cancer screening, bone density tests, blood glucose tests, prostate cancer screening, flu shots, glaucoma tests, and blood tests and other screening for diabetes, heart disease, and certain cancers.