Medicare Program Basics
What to know
The exam treats Medicare as four parts plus a set of eligibility rules. Part A is hospital insurance (inpatient, skilled nursing after a qualifying stay, hospice, some home health); most people get it premium-free with 40 quarters of Medicare-taxed work. Part B is medical insurance (physician services, outpatient, durable medical equipment, preventive care) and carries a monthly premium that rises with income (IRMAA). Part C is Medicare Advantage, and Part D is outpatient prescription drug coverage delivered through private plans. Original Medicare is fee-for-service with deductibles and 20% coinsurance for many Part B services and no out-of-pocket maximum; Medigap and Part D can be added. Know the enrollment windows: the Initial Enrollment Period is the 7-month span around the 65th birthday month (or based on disability/ESRD), the General Enrollment Period runs January 1–March 31 with coverage starting the following month, and the Medicare Advantage Open Enrollment Period is January 1–March 31.
Traps
Questions blur "who is eligible" with "what is covered." People with ESRD generally may enroll in Medicare Advantage, but the rules differ from age-based eligibility. Hospice is covered under Part A even when the person is in a Medicare Advantage plan. Skilled nursing facility care requires a prior qualifying inpatient hospital stay and is not the same as custodial long-term care, which Medicare does not cover. Do not confuse Part B premium assistance (Medicaid/QMB) with Part D Extra Help.
Rule of thumb
If the service is custodial, long-term, or purely routine dental/vision/hearing, assume Original Medicare does not cover it unless a specific provision says otherwise.