What Is Medicare Part B (Medical Insurance)?

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Medicare Part B, along with Medicare Part A, is part of Original Medicare. Enrollment in Medicare automatically includes enrollment in Part B, which covers doctor visits, medical treatments, and medical supplies.

Medicare Part B Eligibility

Automatic Eligibility at Age 65

You are eligible for Medicare Part B coverage If you:

  • are at least 65 years old,
  • are a U.S. citizen or have been a permanent legal U.S. resident for five years, and
  • are eligible to collect retirement benefits from Social Security or the Railroad Retirement Board.

Limited Eligibility Before Age 65

If you are under 65 years old, you may be eligible for Medicare Part B coverage if you are a U.S. citizen or have been a permanent legal U.S. resident for five years, and:

  • you receive disability benefits from the Social Security Administration,
  • you have end-stage renal disease (ESRD), or
  • you have amyotrophic lateral sclerosis (ALS).

Learn more about the age requirements for Medicare

Medicare Part B Enrollment

Automatic Enrollment at Age 65 For Retirement Beneficiaries

Enrollment in Medicare Part B is usually automatic for persons already receiving retirement benefits from Social Security or the Railroad Retirement Board when they reach age 65. Persons automatically eligible receive their permanent Medicare card about three months before turning 65.

Manual Enrollment For Persons Ineligible for Automatic Enrollment

Persons who are eligible for Medicare Part B coverage but do not qualify for retirement benefits from Social Security or the Railroad Retirement Board must take steps to enroll manually for Medicare Part B coverage. Application for coverage can be made at the Social Security website, visiting a Social Security office, or by telephone (1-800-772-1213 / TTY users 1-800-325-0778).

Original applications should be made during a person’s Initial Enrollment Period (IEP).  The IEP begins three months before an applicant turns 65 and ends three months after the applicant’s 65th birthday.

Medicare Part B Coverage

Medically necessary services: Services or supplies that are needed to diagnose or treat your medical condition and that meet accepted standards of medical practice.

Medical Services Covered

Treatments needed to diagnose and treat medical conditions that meet the accepted standards of medical practice are covered. This includes outpatient treatments and appointments at doctors’ offices. Preventative care and necessary laboratory tests are also normally covered.

Medical Supplies Covered

Durable medical equipment necessary to treatment is covered by Medicare Part B. Covered items include wheelchairs, walkers, and oxygen tanks. Medical supplies can be obtained from approved suppliers when ordered by an approved medical care provider.

 Ambulance Services

Necessary emergency ambulance transportation to care facilities is covered by Medicare Part B.

Part-time Home Health Care and Rehabilitation

When a patient is home-bound, some part-time care is covered, including skilled nursing care and physical therapy.

Prescription Drugs

Medicare Part B covers drugs administered in-office by your provider. Some outpatient prescriptions are covered in limited cases usually related to chemotherapy treatments. Medicare Part D generally relates to prescription drug coverage, and any drugs covered by Medicare Part B cannot be covered by Medicare Part D.

Medicare Part B Premiums

Unlike Medicare Part A, Medicare Part B coverage normally involves a monthly premium for covered persons. Part B premiums are adjusted annually and currently begin at $135.50 per month. Covered persons with higher incomes will pay higher premiums. Monthly premiums are normally deducted from monthly retirement benefits received from Social Security or the Railroad Retirement Board.

Medicare Part B typically involves more costs than Medicare Part A, and some people delay enrollment in Part B when they still have coverage through their work or their spouse’s coverage. Persons who defer Medicare Part B coverage are typically eligible to enroll without late penalties during qualified special enrollment periods of up to eight months.

Medicare Part B Deductibles

The annual deductible for Medicare Part B coverage is subject to adjustment each year and is currently $185.

Medicare Part B Coinsurance

Many covered services require a 20% coinsurance payment for each covered service. Providers who accept Medicare Part B coverage normally agree to not charge patients more than the amount approved by Medicare for any covered service.

Other Medicare Coverages

Medicare Part B is part of Original Medicare, which includes Medicare Part A. Medicare Part C involves Medicare Advantage plans that combine parts of coverages under Parts A and B.

Medicare Part D involves prescription drug coverage. Click the links below for more information on the other parts of Medicare coverage.