Older adults have a higher risk of developing a wide range of medical conditions, which is why it’s so important to see a doctor regularly as you age. Keeping up with your preventive care and getting recommended screenings can help you avoid serious health problems down the road, but it can also be expensive. In 1965, Congress tried to remedy this problem by passing what’s known as the Medicare Law, a set of amendments to the Social Security Act that established the Medicaid and Medicare programs. Medicare is a health insurance program that ensures older people have access to health services even if they can’t afford private health insurance.

In its infancy, Medicare was reserved just for senior citizens, but it’s now available to some younger people with documented disabilities. The program has also expanded to cover additional services to ensure older adults can get the care they need. If you’re nearly eligible for Medicare or you care for someone who is, it’s important to understand the eligibility guidelines and the benefits offered.

This guide provides an in-depth overview of Medicare Part B, which gives you medical insurance to help pay for doctor visits, outpatient lab tests and a wide variety of other services. It also explains how to enroll and answers some frequently asked questions about Medicare Part B. You can use this information to make Medicare-related decisions for yourself or a loved one.

What Is Medicare Part B?

Medicare Part B is a component of Original Medicare, a health insurance program managed by the federal government. Original Medicare has two components: Hospital Insurance (Part A) and Medical Insurance (Part B). The Medical Insurance portion pays for many of the services you receive on an outpatient basis, such as X-rays and immunizations. It also covers emergency room services and the care provided by doctors you see when you’re in the hospital.

Medicare has some other components that are different from Part B. Medicare Advantage, also known as Medicare Part C, bundles the coverage of Part A and Part B into a single plan that may also cover additional services. Medicare Part B is different from Part C because it’s managed by the federal government; in contrast, Medicare Part C plans are sold by private insurers. Original Medicare doesn’t cover most prescription drugs, so Medicare Part D gives you the option of buying supplemental drug coverage. Part D only covers prescriptions, while Part B covers a variety of medical services.

Medicare Part A vs. Medicare Part B

Although Medicare Part A and Medicare Part B are both part of Original Medicare, they cover different things. Medicare Part A pays for inpatient hospital care, hospice care, home health services and care in a skilled nursing facility. In contrast, Medicare Part B covers many of the services you receive at your doctor’s office and other outpatient facilities, such as laboratories and imaging centers. It also covers emergency services and care provided by doctors when you’re in a hospital, psychiatric center or another Medicare-approved inpatient facility. Both parts work together to ensure you have comprehensive health coverage.

One of the major differences between Medicare Part A and Medicare Part B is the out-of-pocket costs associated with each one. If you paid Medicare taxes for at least 40 quarters, you’ll qualify for premium-free Medicare Part A, but you must pay a monthly premium for your Part B coverage. In 2021, the standard Part B premium is $148.50 per month; however, you may have to pay a higher premium if you have a high income. The Part A deductible is $1,484 per benefit period for inpatient hospital care, while the Part B deductible is $203 per calendar year as of 2021. Medicare Part A and Medicare Part B also have different coinsurance and copay requirements.

What Does Medicare Part B Cover?

Medicare Part B (Medical Insurance) covers three major types of services: outpatient care, preventive health services, and durable medical equipment. It also covers a few things that don’t fit into any of these categories. For example, if you’re admitted to a hospital, you may have several doctors caring for you during your stay. Medicare Part B covers the services provided by these doctors. If you need to visit the emergency room, Medicare Part B also pays for the services you receive there.

In general terms, Medicare Part B pays for preventive services and medically necessary services. Preventive services are those you receive to help prevent illnesses or detect them as early as possible so you have the best chance of a positive outcome. Medically necessary services are those needed to diagnose or treat a medical condition. For example, if you have symptoms of a heart problem, you may need to have an echocardiogram (ultrasound of the heart) or a blood test to check your cholesterol and triglyceride levels. In addition to the services described below, Medicare Part B covers clinical research, ambulance transportation and certain mental health services.

Outpatient Care

Medicare Part B covers a variety of medical services delivered on an outpatient basis. Emergency room care and observation services are covered under Part B rather than Part A. If you have blood drawn at a hospital laboratory, Medicare Part B will cover it as long as you’re not admitted at the time. Medicare Part B also covers X-rays and other imaging tests performed at a hospital, provided you have them on an outpatient basis and not while you’re admitted. 

Although Original Medicare doesn’t cover most drugs, Medicare Part B does offer limited drug coverage in certain circumstances. If you have end-stage renal disease, Part B may pay for your oral ESRD medications, as long as those medications are also available in injectable form and your benefit covers them. Drugs delivered via an infusion pump or some other type of durable medical equipment may also be covered, along with injectables administered by a medical professional, blood-clotting factors and some antigens.

Preventive Health Services

Medicare Part B covers a wide range of preventive health services, including dozens of screenings that can help detect illnesses in their early stages. It’s important to follow your doctor’s recommendations regarding these screenings, as early detection makes it more likely that you’ll be able to treat the illness successfully. Medicare Part B covers screenings for cervical cancer, colorectal cancer, diabetes and osteoporosis, among other health conditions. It also covers the immunizations you receive to protect you against infectious diseases. For example, Medicare Part B will cover your annual flu shot to prevent you from getting influenza.

Durable Medical Equipment

The durable medical equipment category includes items that generally have a lifespan of at least three years. Durable medical equipment is used for health purposes, can be used in your home and generally isn’t useful to someone who doesn’t need it for a medical condition. Medicare Part B covers many types of durable medical equipment, such as canes, walkers, wheelchairs, infusion pumps, blood sugar meters and oxygen equipment. For Medicare Part B to pay for your durable medical equipment, you must get it from a supplier enrolled in Medicare.

What Isn’t Covered by Medicare Part B?

You can get many medical services under your Medicare Part B coverage, but it doesn’t cover everything you might need. For example, Medicare doesn’t cover custodial care in the patient’s home or an institution, or personal care that can be provided by someone who isn’t a skilled medical professional. This means Medicare won’t cover nursing home care. Part B also doesn’t cover dentures, most dental services, acupuncture, routine foot care, hearing aids or eye exams that you need to get eyeglasses.

How Much Does Medicare Part B Cost?

Although you may pay less for Medicare than you did for group health coverage or some other type of health insurance, it’s not completely free. You’ll have to pay a monthly premium for your Part B coverage, along with deductibles and coinsurance. In 2021, the standard Part B premium is $148.50 per month. Your premium may be higher if the modified adjusted gross income (MAGI) on your tax return from two years ago was more than $88,000 (single or married filing separately) or $176,000 (married filing jointly). The table below shows how much you can expect to pay for Medicare Part B based on your MAGI. If you’re not ready to enroll in Medicare Part B just yet, these amounts may increase slightly by the time you sign up.

Single/Married Yearly IncomeMonthly premium per person
More than $88,000/$176,000$207.90
More than $111,000/$222,000$297.00
More than $138,000/$276,000$386.10
More than $165,000/$330,000$475.20
More than $500,000/$750,000$504.90

For 2021, the Medicare Part B deductible is $203. You must pay the deductible before Medicare starts paying any of your medical costs. Once the deductible is paid, you’ll have to pay a coinsurance of 20% of the Medicare-approved amount for each service you receive. For example, if the Medicare-approved amount is $100, you’d pay $20. Medicare Part B would cover the rest. Medicare Part B doesn’t usually have any copays, which are fixed amounts that you pay for each service.

Who Is Eligible for Medicare Part B?

To get Medicare Part B coverage, you must be eligible for Medicare. Originally, the program was intended exclusively for senior citizens, but it has since grown to include younger people with a wide range of disabilities. If you’re under 65 and want to enroll in Medicare due to a disability, you must meet certain guidelines. For example, your disability must be documented by a medical professional. In many cases, you also need to receive 24 disability payments from the Social Security Administration or Railroad Retirement Board before you’re eligible for Medicare. One notable exception is if you’re diagnosed with Lou Gehrig’s disease (ALS). If you receive an ALS diagnosis, you don’t have to wait 24 months to qualify for Medicare benefits.

You must also meet two other eligibility requirements. First, you must be a U.S. citizen or lawful permanent resident. Second, if you’re a lawful permanent resident, you must live in the United States for at least five continuous years (five years in a row) before you qualify for Medicare. It doesn’t count if you lived here for two years, left for a year and then came back for three more years.

To summarize, you need to meet the following eligibility requirements to qualify for Medicare Part B:

  • U.S. citizen or lawful permanent resident
  • At least 65 years old OR have a documented disability
  • For most disabilities, receive 24 disability payments before qualifying

How Do I Enroll in Medicare Part B?

medicare enrollment form

When you’re ready to enroll, timing is everything. Although you can sign up for Medicare Part A at any time once you become eligible, you don’t have the same flexibility with Medicare Part B. You need to sign up during certain enrollment periods, or you may have to pay a higher premium the rest of the time you’re on Medicare. 

Initial Enrollment Period

The initial enrollment period is your first opportunity to enroll in Medicare Part B. It starts three months before you turn 65 and ends three months after your 65th birthday month. You can sign up any time during this seven-month period, but it’s best to enroll as early as possible, as your coverage will be delayed if you wait until the month of your birthday to sign up. If you have health coverage that will end before your Medicare Part B coverage goes into effect, then you’ll have a coverage gap that could be costly if you need care while you don’t have insurance.

General Enrollment Period

If you don’t sign up during your initial enrollment period, you’ll have another opportunity during the general enrollment period. This happens every year from January 1 to March 31. Although you can sign up during this period, you may have to pay a late enrollment penalty. The penalty takes the form of a premium increase that remains in effect for the life of your Medicare coverage, so try your best to enroll during your initial enrollment period instead of waiting.

Special Enrollment Periods

Normally, you can’t enroll in Medicare Part B outside the initial enrollment and general enrollment periods, but there are some exceptions known as special enrollment periods. You may qualify for a special enrollment period if you have group health coverage through an employer or a labor union and meet one of the following conditions:

  • You’re working
  • Your spouse is working
  • Your family member is working (if you’re disabled)

This special enrollment period allows you to sign up for Medicare Part B at any time. You may also qualify for a special eight-month enrollment period that at the following times:

  • After your group health coverage ends
  • After your employment ends

The special enrollment period begins 30 days after one of these conditions is met. In many cases, you don’t have to pay the late enrollment penalty if you sign up during a special enrollment period. A special enrollment period is also available if you’re volunteering in a foreign country.

Automatic Enrollment in Medicare Part B

If you start receiving retirement benefits from the Social Security Administration or Railroad Retirement Board at least four months before your 65th birthday, you’ll be automatically enrolled in Medicare Part B. If you’re receiving Social Security or Railroad Retirement Board disability benefits and only have Medicare Part A coverage, you’ll be enrolled automatically in Part B when you turn 65.

If you don’t qualify for automatic enrollment, you’ll have to apply for coverage. You can fill out this application on the Social Security Administration website. If you need help with the application, you can also visit a local Social Security office or call the Social Security Administration at 800-772-1213.

Frequently Asked Questions

How do I sign up for Medicare Part B?

To sign up for Medicare Part B, fill out the application on the Social Security website. If you have questions or need help understanding the application, you can also visit your local Social Security office or call 800-772-1213. Before visiting a local office, call to make sure it’s open. SSA offices are closed on federal holidays, and in-person services may be limited due to the COVID-19 pandemic.

Does Medicare Part B cover preventive screenings?

Yes, Medicare Part B covers a wide range of preventive screenings. These screenings are used to prevent illnesses or diagnose illnesses as early as possible before they have a chance to cause complications. Medicare Part B covers screenings for osteoporosis, several types of cancer, diabetes, glaucoma and other chronic health conditions.

How much does Medicare Part B cost?

In 2021, the standard premium for Medicare Part B is $148.50 per month. Depending on your modified adjusted gross income, you may have to pay up to $504.90 per month. You also need to be aware of the out-of-pocket costs you incur each time you receive medical care. In addition to a deductible of $203 per year, you must pay 20% of the Medicare-approved amount for most services.

What kinds of expenses does Medicare Part B cover?

Medicare Part B covers outpatient care, preventive screenings, durable medical equipment, emergency room care, ambulance transportation and clinical research. If you’re admitted to a hospital, it also covers the fees of the doctors who manage your care while you’re an inpatient.

What is the Medicare Part B deductible for 2021?

For 2021, the Medicare Part B deductible is $203. You must pay the deductible in full before Medicare starts covering your medical expenses. Once the deductible has been met, you typically have to pay 20% of the Medicare-approved amount for each service.