Medicare is a social insurance program defined and administered by the United States government, to provide health insurance coverage to people aged 65 and above, or who meet a few other special criteria.

The original Medicare program has two parts: Medicare Part A (Hospital Insurance), and Medicare Part B (Medical Insurance). Prescription drugs are normally not covered by original Medicare. Medicare Part D plans provides more comprehensive drug coverage. Medicare Part C, also known as Medicare Advantage plan is another way for beneficiaries to receive their Medicare Part A ,B and Medicare D benefits.

More about Medicare Part B
Medicare Part B medical insurance helps pay for some services and products not covered by Part A, generally on an outpatient basis. Part B is optional and may be deferred if the beneficiary or their spouse is still actively working.

• Initial Enrollment Period. You can enroll in Medicare Part B with the Social Security office eight months before and four months after becoming eligible for Medicare benefits. If you enroll during this period there are no penalties and your coverage will be effective on either the date of eligibility or the first of the month after enrolling, whichever is late
• Special Enrollment Period is available when you did not enroll in Medicare Part B because you were covered by an employer or union group health plan. There is generally no penalty added to the premiums for enrolling in Part B during the Special Enrollment Period.
• General Enrollment Period is available each year if you did not enroll during the Initial Enrollment Period and are not eligible for the Special Enrollment Period. People who enroll during this period generally must pay a penalty.You may enroll in the first three months (January 1 through March 31) of any calendar year. You will have to pay a penalty for enrolling during the general enrollment period. The penalty is 10% additional for each full twelve-month period from the expiration of the Initial Enrollment Period to the end of the General Enrollment Period during which you enroll. Once imposed, you pay the surcharged premium as long as you have Part B.

Medicare Part B
Medicare Part B coverage includes nursing and physician services, laboratory, x-rays, and diagnostic tests, pneumonia and influenza vaccinations, blood transfusions, renal dialysis, outpatient hospital procedures, limited ambulance transportation, immuno suppressive drugs for organ transplant recipients,chemotherapy, hormonal treatments such as Lupron, and other outpatient medical treatments administered in a doctor’s office. Medication administration gets covered under Part B if administered by the physician during an office visit.

Part B also helps with durable medical equipment (DME), including canes,walkers,wheelchairs, and mobility scooters for those with mobility impairments. Prosthetic devices like artificial limbs and breast prosthesis following mastectomy, one pair of eye glasses following a cataract surgery, and oxygen for home use is also covered.[9] Complex rules are used to manage the benefit, and advisories are periodically issued which describe coverage criteria. On the national level these advisories are issued by CMS, and are known as National Coverage Determinations (NCD). Local Coverage Determinations apply only within a multi-state area that is managed by a Medicare Part B contractor, and Local Medical Review Policies (LMRP) were superseded by LCDs in 2003.

Medicare Part D Plans
Medicare D went into effect on January 1, 2006. Anyone with Part A or B is eligible for Medicare Part D Plans. This became possible due to the passage of the Medicare Prescription Drug, Improvement, and Modernization Act. In order to receive this benefit, a person with Medicare must enroll in a stand-alone Prescription Drug Plan (PDP) or Medicare Advantage plan with prescription drug coverage (MA-PD). These plans are approved and regulated by the Medicare program, but are actually designed and administered by private health insurance companies. Unlike Original Medicare Part A and B, Medicare Part D Plans are not standardized. The plans choose which drugs (or even classes of drugs) they wish to cover, at what level (or tier) they wish to cover it, and are free to choose not to cover some drugs at all. As an exception, Medicare specifically excludes certain drugs from Medicare part D coverage, including but not limited to benzodiaze pines,cough suppressant and barbiturates.Plans that cover excluded drugs are not allowed to pass those costs on to Medicare D, and plans are required to repay CMS if they are found to have billed Medicare in these cases.