What Medicare Part B Covers and What It Doesn't

Medicare Part B covers doctor visits, outpatient care, and some preventive services

Medicare Part B is the medical insurance portion of Original Medicare. It pays for visits to doctors and specialists, lab tests, X-rays, outpatient surgery, and certain medical equipment and supplies. Part B does not cover hospital stays (that is Part A), prescription drugs (that is Part D), or most dental, vision, or hearing care.

Part B is optional, but most people who have Part A enroll in it. You pay a monthly premium for Part B — the standard amount changes each year. After you meet your annual deductible, Medicare pays 80 percent of covered services, and you pay 20 percent. There is no yearly limit on what you pay out of pocket.

Part B covers the same services whether you see a doctor who accepts Medicare assignment or not, but your costs differ. A doctor who accepts assignment agrees to accept Medicare's payment as full payment for covered services. If your doctor does not accept assignment, you may owe more.

Key Takeaways

Part B covers doctor office visits, specialist consultations, lab work, imaging, and outpatient procedures, but you pay 20 percent of the cost after your deductible.
Part B does not cover hospital inpatient stays, prescription drugs, dental work, vision care, hearing aids, or most routine foot care.
You must enroll in Part B during your initial enrollment period or face a permanent late penalty on your premium.
Preventive services covered by Part B — such as cancer screenings, cardiovascular tests, and diabetes monitoring — are covered at no cost to you when you see an in-network provider.
If you have a Medigap or Medicare Advantage plan, your out-of-pocket costs for Part B services may be lower than Original Medicare alone.

Doctor visits and specialist care covered by Part B

Part B pays for office visits to your primary care doctor and to specialists such as cardiologists, orthopedists, and neurologists. The visit must be medically necessary — meaning your doctor documents that you need it to diagnose or treat a condition. Routine checkups without a specific medical reason are not covered, though preventive visits are.

When you see a doctor who accepts Medicare assignment, you pay your 20 percent coinsurance after you have met your annual deductible. In 2024, the Part B deductible is $240, but this amount changes yearly. Once you have paid $240 out of pocket for Part B services in a calendar year, Medicare begins paying its 80 percent share.

If your doctor does not accept assignment, you may owe more than 20 percent. Non-participating doctors can charge up to 15 percent above Medicare's approved amount — this is called balance billing. Before your visit, ask whether your doctor accepts Medicare assignment.

Lab tests, imaging, and diagnostic services

Part B covers blood tests, urinalysis, and other lab work ordered by your doctor. It also covers X-rays, CT scans, MRI scans, ultrasounds, and EKGs when they are medically necessary. These services are covered whether they happen in a hospital outpatient department, an imaging center, or a doctor's office.

You pay 20 percent of the Medicare-approved amount after your deductible. If the facility or lab does not accept assignment, you may owe balance billing charges. Ask your doctor's office or the imaging center whether they accept Medicare assignment before your appointment.

Outpatient surgery and procedures

Part B covers surgery and procedures done in a hospital outpatient department or an ambulatory surgical center — places where you do not stay overnight. Examples include cataract removal, joint injections, skin biopsies, and minor orthopedic procedures. Part B also covers some procedures done in a doctor's office, such as removal of skin lesions or wart treatment.

You pay 20 percent coinsurance after your deductible. If the procedure is done in a hospital outpatient department, you may also owe a facility fee in addition to the surgeon's fee. Ask your surgeon's office what the total out-of-pocket cost will be before the procedure.

Preventive services with no cost to you

Medicare Part B covers many preventive services at no cost when you see a doctor or facility that accepts Medicare assignment. These include cancer screenings (mammograms, colonoscopies, Pap tests), cardiovascular screenings (EKG, stress tests), diabetes screenings and monitoring, bone density scans, and vaccines (flu, pneumonia, shingles, RSV).

You do not pay a copay, coinsurance, or deductible for these covered preventive services. However, if your doctor finds a problem during a preventive visit and performs additional testing or treatment, you may owe coinsurance for those extra services. For example, a screening colonoscopy is free, but if polyps are removed during the procedure, you pay 20 percent of the removal cost.

Medical equipment and supplies Part B covers

Part B covers durable medical equipment (DME) — items such as wheelchairs, walkers, canes, oxygen equipment, CPAP machines, and hospital beds. It also covers diabetic supplies (test strips, lancets, glucose monitors) and ostomy supplies. Your doctor must order the equipment, and you typically rent rather than buy it, though some items can be purchased.

You pay 20 percent of the Medicare-approved rental or purchase price after your deductible. The supplier must be Medicare-enrolled. If you need equipment, ask your doctor for a written order and request a list of Medicare-approved suppliers in your area.

What Part B does not cover

Part B does not cover hospital inpatient stays — that is Part A's role. It does not cover prescription drugs taken at home; those are covered by Part D. Part B does not cover most dental work, routine eye exams, eyeglasses, contact lenses, hearing aids, or routine foot care (such as toenail trimming or callus removal).

Part B does not cover cosmetic surgery, weight loss surgery, or fertility treatment. It does not cover acupuncture, chiropractic care, or massage therapy. It does not cover most physical therapy, occupational therapy, or speech therapy unless they are part of a covered outpatient rehabilitation program or home health service.

Part B does not cover care you receive outside the United States, except in limited situations near the U.S. border or on a ship within U.S. territorial waters. If you travel internationally, you may want to purchase supplemental travel insurance.

How your costs work with Part B

Your Part B costs have three parts: the monthly premium, the annual deductible, and coinsurance. The monthly premium is automatically deducted from your Social Security check or billed to you directly. In 2024, the standard premium is $174.70 per month, but higher-income beneficiaries pay more.

The annual deductible ($240 in 2024) applies to most Part B services except preventive care. Once you have paid the deductible, you pay 20 percent coinsurance for most services. There is no yearly out-of-pocket maximum under Original Medicare Part B — your costs can continue to accumulate throughout the year.

If you have a Medigap policy (supplemental insurance), it may pay your deductible and coinsurance, lowering your out-of-pocket costs. If you have a Medicare Advantage plan, you may have lower coinsurance or copays, but you must use doctors and facilities in the plan's network.

Frequently Asked Questions

Do I have to enroll in Part B when I turn 65?

Part B is optional, but if you do not enroll when you are first may be able to access, you will pay a permanent penalty on your monthly premium for as long as you have Medicare. The penalty is 10 percent for each full year you could have had Part B but did not. If you are still working and have health insurance through your employer, you may be able to delay enrollment without penalty.

What happens if my doctor does not accept Medicare assignment?

You can still see the doctor, but you may owe balance billing — up to 15 percent more than Medicare's approved amount. Before your visit, ask the doctor's office whether they accept assignment. If they do not, ask what your total out-of-pocket cost will be.

Are mental health services covered by Part B?

Yes. Part B covers visits to psychiatrists, psychologists, clinical social workers, and nurse specialists for mental health treatment. You pay 20 percent coinsurance after your deductible, the same as for other doctor visits. Some preventive mental health screenings are covered at no cost.

Does Part B cover physical therapy?

Part B covers physical therapy, occupational therapy, and speech therapy when they are part of a covered outpatient rehabilitation program or home health service ordered by your doctor. You pay 20 percent coinsurance after your deductible. There are annual visit limits for some therapy services.

What should I do if I receive a bill I think Part B should have covered?

Contact your doctor's office first to confirm the service was billed to Medicare. If it was, request an itemized bill and the reason for denial. You can also call Medicare at 1-800-MEDICARE to ask about the claim or file an appeal if you believe the service should have been covered.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.