Medicare Part B Coverage

Medicare Part B coverage pays for outpatient medical care, the doctor visits, tests, and outpatient procedures that happen outside a hospital admission. Part B is the second piece of Original Medicare, working alongside Part A hospital insurance to cover the services people use most often: primary care and specialist visits, outpatient hospital care, preventive screenings, durable medical equipment (DME), and limited home health services. After you meet the annual Part B deductible, Medicare typically pays 80% of the approved amount for a covered service and you pay the remaining 20% coinsurance, unless a Medicare Supplement plan covers that share for you. Here is what Part B actually covers, where the gaps are, and how the costs play out in common situations.

Doctor and specialist visits. Part B covers medically necessary services from doctors and most specialists, including office visits, consultations, and second opinions. After you meet your annual deductible, you typically pay 20% coinsurance for these visits unless you carry a Medicare Supplement plan that covers the gap. A Medigap Plan G policy, for instance, pays that 20% coinsurance in full for Part B-covered services, which is why many people pair Original Medicare with a supplement rather than relying on Part B coinsurance alone. Medicare Advantage plans handle this cost-sharing differently, usually through copays instead of a flat coinsurance percentage.

Outpatient hospital and surgery. Outpatient hospital services fall under Part B even when you receive them at a hospital. This includes emergency room visits that do not result in an inpatient admission, ambulatory surgery, lab work, imaging, and observation status. Observation status is one of the more confusing parts of Medicare: even if you spend the night in a hospital bed, you may be classified as an outpatient under observation rather than admitted as an inpatient. That distinction matters because observation stays are billed under Part B rules, not Part A, and observation time does not count toward the three-day inpatient stay Medicare requires before it will cover a skilled nursing facility stay.

Preventive care. Many preventive services are covered at $0 out of pocket when you see a provider who accepts Medicare assignment, meaning no deductible or coinsurance applies. Covered preventive services include the annual wellness visit, mammograms, colonoscopies, flu and pneumonia shots, and screenings for diabetes, depression, and cardiovascular disease. Confirm with your provider that a visit is billed as preventive rather than diagnostic, since raising a new health concern during a wellness visit can shift part of that visit into standard Part B cost-sharing.

Durable medical equipment (DME). DME covers items like wheelchairs, walkers, oxygen equipment, and hospital beds when a doctor certifies they are medically necessary for use in your home. As with most Part B services, you typically pay 20% coinsurance after your deductible, and Medicare only covers equipment from suppliers enrolled in the program. Some DME items require prior authorization before Medicare will pay a claim, which can add processing time. See our guide to Medicare prior authorization for how that approval process works.

Home health care. Part B also covers a limited slice of home health care: part-time or intermittent skilled nursing care, physical and occupational therapy, and medical social services, when a doctor certifies you are homebound and need skilled care. It does not cover full-time home care or custodial help with daily activities like bathing and dressing on its own. Home health coverage can involve both Part A and Part B depending on the situation, so it is worth understanding the specific rules before assuming a service is covered. See our guide on what Medicare covers for home health care for a fuller breakdown.

What Part B does not cover. Part B leaves several common expenses uncovered:

• Most self-administered prescription drugs, which fall under Part D drug coverage instead
• Routine dental, vision, and hearing care
• Long-term custodial care
• Cosmetic procedures

Many beneficiaries add a separate Part D plan and a dental, vision, and hearing plan specifically to fill these gaps.

Part B costs and enrollment timing. Part B comes with a monthly premium and an annual deductible that Medicare sets and updates each year. Higher earners pay an additional Income-Related Monthly Adjustment Amount (IRMAA) on top of the standard premium, based on income reported two years earlier. Enrollment timing matters too: if you delay signing up for Part B without other creditable coverage, such as an employer group health plan, Medicare can add a late enrollment penalty to your premium for as long as you have Part B. If you are approaching 65 or weighing when to enroll, our guides on turning 65 and the Medicare late enrollment penalty walk through the deadlines and exceptions.