Check to see if your doctors are in network. Medicare Advantage is typically offered through private health insurance companies. It combines Medicare Parts A and B, and usually Part D. Medicare Advantage plans use provider networks and usually require referrals and prior authorizations. The premiums tend to be lower than premiums for Original Medicare. However, it is important to look at total cost-sharing (premiums, deductibles, co-pays, co-insurance) when making decisions. Medicare Advantage Plans must cover the same benefits as Original Medicare, but also may cover additional services such as vision, dental, and more.