Medigap health insurance plans are used to help pay for some of the healthcare services covered/allowed by Medicare but not fully paid for. In other words, it helps fill some of the gaps of Original Medicare coverage.

There are several Medigap plans to choose from. Unfortunately, the plans are lettered, so it can be confusing when you see Medigap plans with the same plan letter as the parts of Medicare we have summarized above.

To see all the Medigap plans offered, go to our What is a Medicare Supplement (Medigap) plan page.

Medicare Part D plans were first made available in 2006. They provide coverage for prescription drugs purchased in a pharmacy setting (or via mail order). A Part D prescription drug plan does not pay for 100% of your prescription costs, rather it pays a portion (if the drug is on the Part D prescription drug plan’s formulary). A cost-share is involved, so you will still owe a copay when picking up your prescriptions.

Coverage and drug copays are primarily based on a drug’s tier (usually Tiers 1 through 5). A drug in a lower tier will generally cost less than a higher tier drug.

To see all the details on how Part D coverage works, go to our Part D Drug Phases page.

Part C is another name for what most people call a Medicare Advantage Plan. Rather than running medical claims through Medicare first and then a Medigap (Medicare Supplement) plan…and then purchasing a stand-alone Part D prescription drug plan, you would use the Medicare Advantage plan to file all medical and prescription drug claims. You don’t need your Original Medicare card in this case (just file it away in a safe place).

Part C (Medicare Advantage) plans typically combine Parts A, B and D in one plan…though, some Medicare Advantage plans are available without Part D prescription drug coverage (i.e. when you already have creditable prescription drug coverage through another source, such as the VA).