Medicare terms

Learn more about Medicare. Start with these definitions.


activities of daily living (ADL)

Activities of daily living refers to such activities as bathing, getting dressed, using toilet facilities, eating and moving place to place. Health professionals may gauge the functional status of an individual by their ability to perform ADLs.

A person who is unable to perform ADLs may need custodial care. This is not covered by Medicare, although that person’s medical needs — as opposed to custodial needs — would be covered by Medicare as long as the person is enrolled in Medicare.

So nursing home care is not covered by Medicare, since it’s intended to provide assistance with ADLs. (Seniors in nursing homes still receive coverage under Medicare when they need medical care, but the cost of the nursing home itself is not covered by Medicare.)

Medicaid does cover custodial care, for people with low income and assets. So seniors who need assistance with ADLs and who deplete their resources and have low incomes are often covered by both Medicare and Medicaid.

As an alternative to using up your resources in order to qualify for Medicaid if you eventually need assistance with ADLs, you can purchase a private long-term care insurance plan, or save money earmarked for paying for long-term care.

administrative law judge (ALJ)

An administrative law judge is the officer of the court who presides over proceedings when a Medicare enrollee files an appeal, objecting to a Medicare decision (including benefit and premium disputes) or against a Medicare provider.

The Administrative Law Judge hearing program is overseen by the Office of Medicare Hearings and Appeals (OMHA).

adult living care facility

An adult living care facility, otherwise known as an assisted living facility, is a residential care facility that provides support people who can’t safely live by themselves but who don’t need skilled medical services 24 hours a day, and thus don’t need to be in a nursing home, where more intensive care is provided.

This article provides a good summary of the differences between an assisted living facility and a nursing home.

advance beneficiary notice (ABN)

An advanced beneficiary notice – also called a “waiver of liability” – is a notice that Medicare providers and suppliers are obligated to give to an Original Medicare enrollee when they find that Medicare does not cover the services the enrollee requests.

advance directive

An advance directive is a legal document that describes your wishes for your medical care and case management in the event that you’re not able to communicate them yourself.

Advance directives include a power of attorney document (in which you designate a person to make medical decisions for you if you are unable physically or mentally to make those decisions yourself), and a living will (in which you detail your specific wishes regarding your medical care, including types of treatment that you do or do not want to receive, whether you want to be an organ donor, etc.). This Mayo Clinic resource provides more information about advance directives.

affiliated provider

An affiliated provider is a person or health care facility paid by your health care plan to provide service to you.

affordable care act (ACA)

The Patient Protection and Affordable Care Act (PPACA) – also known as the Affordable Care Act (ACA) – is the landmark health reform legislation signed into law by President Barack Obama in 2010. Key provisions extended coverage to millions of uninsured Americans, implemented measures to lower health care costs and improve system efficiency, and eliminated insurance industry practices that included rescission and denial of coverage due to pre-existing conditions.

The bulk of the ACA’s insurance provisions applied to the individual-market and small-group market, but the law also imposed some new regulations on the large-group market, and on large employers. And some provisions directly affected Medicare.

Like the implementation of Medicare in 1965, the Affordable Care Act represented a major shift in US health care regulation. Learn about the similarities (and differences) between LBJ’s landmark Medicare legislation and the ACA.

The ACA imposed funding cuts on Medicare Advantage plans, to bring federal spending on those plans into line with what the government would spend if those enrollees were in Original Medicare instead. There was speculation that Medicare Advantage enrollment would drop as a result, but enrollment had been steadily increasing every year since 2004, and that trend continued after the ACA was enacted.

For seniors who have Medicare Part D prescription coverage, the ACA included a provision to close the donut hole by 2020, so seniors have been seeing increasingly large discounts on medications purchased while in the donut hole.

Before the ACA was implemented, seniors who were recent immigrants — and thus not eligible to purchase Medicare — had few options for health insurance coverage. But the ACA made it possible for recent immigrants over the age of 64 to purchase individual market coverage, with premium subsidies based on income.

aging in place

Aging in place refers to a decision individuals make to remain in their homes or their communities as they grow older instead of opting for relocation to long-term care facilities such as assisted living and nursing homes.

The decision to remain independent and at home will likely involve consideration of in-home care provided by caregivers who can assist with individuals who might have difficulty with activities of daily living.

ambulatory care

Ambulatory care refers to health care services that do not include a stay in a hospital, otherwise known as outpatient care. Ambulatory care can be provided in a hospital — emergency room treatment is a common example, as is outpatient surgery that does not require an overnight stay in the hospital. But if the patient ends up being admitted as an inpatient, the care would be inpatient rather than ambulatory.

Medicare Part B covers ambulatory care, whereas Medicare Part A covers inpatient care.

amyotrophic lateral sclerosis (ALS) or lou gehrig’s disease

Patients who suffer from amyotrophic lateral sclerosis (ALS) are eligible for Medicare at any age. The disease attacks a person’s motor nerve cells in the spinal cord.

Patients with ALS become eligible for Medicare as soon as they begin collecting Social Security disability benefits. There’s a five-month waiting period before applicants with ALS can begin receiving Social Security disability payments, and Medicare takes effect at the same time as the disability payments.

This is in contrast to Medicare for other types of disabilities, when there is typically a two-year delay between the start of disability benefits and the start of Medicare eligibility.

ancillary services

Ancillary services are medical services provided in a hospital while a patient is an inpatient, but paid by Medicare Part B (outpatient care) when the Part A (hospitalization) claim is denied because Medicare believes that it was unreasonable or unnecessary for the person to be admitted as an inpatient. Ancillary services include things like diagnostic x-rays and lab tests, prosthetic devices, physical therapy, and various screening tests, among others.

In 2013, CMS proposed regulations (finalized in 2014) to make it easier for hospitals to rebill services to Medicare Part B if a claim to Medicare Part A is denied. So instead of just being able to obtain payment for the limited list of ancillary services that were previously eligible for Part B coverage in that situation, hospitals can now rebill most services under Part B if the Part A claim is denied.

annual coordinated election period (ACEP) or annual election period

Annual coordinated election period (ACEP) or annual election period refers to the period of time between October 15 and December 7 during which you can change your Medicare prescription drug coverage or your Medicare Advantage plan (including switching from Original Medicare to a Medicare Advantage plan). ACEP is also the period of time during which you can enroll in Medicare Part D, if you missed your Initial Enrollment Period.


annual election period

Medicare’s annual election period – also known as Medicare open enrollment – is the annual period during which Medicare plan enrollees can reevaluate their coverage and make changes.

During open enrollment, a beneficiary can switch Medicare Advantage plans, switch from Medicare Advantage to Original Medicare or from Original Medicare to Medicare Advantage, join a Medicare Part D prescription drug plan, switch from one Part D plan to another or drop Medicare Part D coverage entirely.

Open enrollment does not apply to Medigap coverage, however.

The enrollment period runs from October 15 to December 7 each year, and changes you make during that time are effective January 1.


An appeal is a formal request to Medicare to have an official decision reviewed in respect to a payment or policy you may wish to dispute.

assigned claim

An approved provider submits an assigned claim to Medicare for payment after you have received a service.

assistive technology

Individuals with disabilities use assistive technology devices to help them function. Medicare does not cover all assistive technologies, but does cover Closed Circuit Television (if a doctor determines it is medically necessary).