Medicare Part B covers costs relating to the diagnosis and treatment of medical conditions. Medicare Part D covers prescription drugs. Specific rules usually apply to both.

Medicare is the federal government’s insurance coverage for those aged 65 and over or with certain medical conditions. Medicare packages have different parts that offer various aspects of medical coverage. Parts B and D are examples of that medical coverage.

This article will explain the differences between Medicare Part B and Part D, including those relating to costs and coverage.

We may use a few terms in this piece that can be helpful to understand when selecting the best insurance plan:

  • Deductible: This is an annual amount that a person must spend out of pocket within a certain time period before an insurer starts to fund their treatments.
  • Coinsurance: This is a percentage of a treatment cost that a person will need to self-fund. For Medicare Part B, this comes to 20%.
  • Copayment: This is a fixed dollar amount that an insured person pays when receiving certain treatments. For Medicare, this usually applies to prescription drugs.

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Medicare Part B and Part D vary in terms of coverage and costs.

Medicare Part B is the portion of Medicare that covers medical services, such as doctor’s visits, durable medical equipment, and select prescription medications.

A person can obtain Part B through Original Medicare and pay their premium to the federal government.

If a person opts for Medicare Advantage, also called Part C, a private insurance company will fulfill Part B benefits. A Medicare Advantage plan must cover everything that Original Medicare covers, and it usually offers additional services.

Medicare Part D covers prescription drugs. The federal government requires that all people aged 65 and over have prescription drug coverage equal to the basic policy that insurance companies offer. Private insurance companies offer Part D plans.

Medicare Part B covers most doctor’s visits and services, as well as durable medical equipment, such as a wheelchair, crutches, or other assistive devices.

Part B does cover some medications that Part D does not. Examples include:

  • antigens that a doctor typically prepares
  • blood clotting factors
  • injectable or infused drugs
  • erythropoiesis-stimulating agents, which doctors commonly use to treat end stage renal disease
  • immunosuppressive drugs
  • injectable medications for osteoporosis
  • intravenous immunoglobulin (IVIG) at home
  • oral medications for end stage renal disease
  • parental and enteral nutrition for IV and tube feeding
  • vaccinations

Part B may also cover other drugs, and a person can check their benefits for information about a specific medication.

Medicare Part D offers a wider range of benefits relating solely to prescription drugs.

Part D plans must provide a listing — also known as a formulary — of prescription drugs. A formulary must cover at least two medications in each major drug category, such as medications to treat blood pressure or diabetes.

Formularies usually have tiers, with generic medications being the least expensive and premium or brand-name medications the most costly.

Both Part B and Part D play an essential role in protecting the health of older adults and those with a disability.

Medicare negotiates approved medical costs to help prevent unfair pricing by medical providers.

Part B

Part B offers the following:

  • coverage for comprehensive medical services
  • limited coverage for prescription medication
  • choice of providers, as long as they accept Medicare

A 20% coinsurance applies to most costs.

Part D

Medicare Part D includes:

  • low cost pricing for commonly prescribed medications
  • deductibles to prevent high medication costs
  • a variety of different plan options to choose from

A person should enroll in Medicare parts B and D when they are first eligible. Waiting until after the Initial Enrollment Period, which ends 3 months after the month in which a person turns 65, could result in additional penalties for the monthly premiums.

The costs for Part B and Part D vary depending on how a person purchases the plan and the options that they choose.

Part B

A person must pay a monthly premium for Medicare Part B. The premiums usually change each year, but for 2021, the standard premium is $148.50.

Part B has a 2021 deductible of $203. A 20% coinsurance for most Medicare-approved services will apply once a person has paid the deductible in full. The coinsurance applies to certain services, including doctor’s visits and prescription drugs.

Part D

People can find the costs for Medicare Part D plans through private insurance companies. The costs for Medicare Part D differ, as prescription drug costs can vary by location.

Many different plans are available, some of which offer comprehensive prescription drug coverage.

In 2021, the average Part D monthly premium is $33.06, which is a 1% increase from 2020, according to the Kaiser Family Foundation.

Private insurance companies offer Medicare Advantage plans and will fulfill a person’s Medicare benefits. These plans may vary in their benefits and costs, depending on the person’s location.

Part B benefits may vary when a person purchases a plan through Medicare Advantage, but the monthly premium will still be applicable.

Medicare Advantage plans may also have differing deductibles, copayments, or coinsurances. A person can carefully compare all of the available plans to determine the one that works best for them.

Medicare Advantage and Part D

A person may choose a Part D plan as part of Medicare Advantage.

Some Medicare Advantage plans have no monthly premiums and include prescription drug coverage. However, a person will likely have to pay a copayment and coinsurance for their prescription medication.

A person who meets the Medicare low-income criteria may qualify for Extra Help. The Extra Help program provides financial support to those who may need assistance to pay for prescription drugs.

Not everyone who turns 65 years of age must have Medicare. Some people may continue to work and choose to utilize their employer’s health insurance or their spouse’s insurance.

In these instances, a person must send documentation to the Centers for Medicare and Medicaid Services (CMS) to show that they have appropriate medical insurance coverage.

If a person is no longer eligible for their own or their spouse’s employer’s health insurance, they may qualify for a Special Enrollment Period during which they are still able to enroll for Medicare coverage.

Unlike some private insurance plans, Medicare accepts all individuals who qualify, without considering preexisting health conditions.

Part B and Part D are two important aspects of Medicare that help beneficiaries pay for their healthcare costs.

Medicare Part D pays for most medications that a person would take at home. In contrast, Medicare Part B may pay for drugs that a person would receive at a doctor’s office, hospital, or infusion center.

Part B also pays for additional services, such as doctor’s visits and some medical procedures.

If a person wants to confirm which part of Medicare covers a particular service, they can call Medicare on 800-633-4227.

The information on this website may assist you in making personal decisions about insurance, but it is not intended to provide advice regarding the purchase or use of any insurance or insurance products. Healthline Media does not transact the business of insurance in any manner and is not licensed as an insurance company or producer in any U.S. jurisdiction. Healthline Media does not recommend or endorse any third parties that may transact the business of insurance.