How Is Medicare Advantage Different From Medigap? 
Medicare Advantage plans are quite different from a Medicare supplement plan , also known as Medigap . When you enroll in a Medicare Advantage plan you are no longer in original Medicare . Your health insurance is covered by a private insurance carrier . Medical providers file your claims with your Advantage carrier , not Medicare . Most Advantage plans have networks you are required to use if you want full coverage . Some Advantage plans provide OON -LRB- out of network -RRB- coverage but with higher deductibles , copay 's and coinsurance . HMO Advantage plans typically have no benefits when you use a non-par provider . With original Medicare you have the freedom to use any doctor , hospital or other medical provider anywhere in the country . There are no networks . Medical providers file claims with Medicare . Once Medicare adjudicates and approves the claim it is forwarded on to your Medigap carrier so they can pay their portion . 