The Medicare system offers beneficiaries a choice between two primary forms of coverage: Medicare Advantage (Part C) and Original Medicare, which can be supplemented with Medigap insurance. Medicare Advantage plans are offered by private companies and bundle Part A (Hospital Insurance) and Part B (Medical Insurance), often including Part D and extra benefits like vision or dental care. Medigap, or Medicare Supplement Insurance, works alongside Original Medicare to help pay for out-of-pocket costs like deductibles, copayments, and coinsurance. Switching from a Medicare Advantage plan to a Medigap plan is possible, but the process is highly conditional based on timing and the individual’s current health status.
The Necessary First Step: Dropping Medicare Advantage
Switching from a Medicare Advantage plan to a Medigap policy is a two-part process. First, the beneficiary must disenroll from their Advantage plan and return to Original Medicare. An individual cannot be enrolled in both a Medicare Advantage plan and a Medigap policy simultaneously, making the exit from Part C a mandatory prerequisite. This disenrollment must occur during a valid enrollment period to ensure a seamless transition of coverage.
The most common window for this action is the Medicare Advantage Open Enrollment Period (MA OEP), which runs annually from January 1st to March 31st. During the MA OEP, a person already enrolled in an Advantage plan can drop it entirely and switch back to Original Medicare. The change takes effect the first day of the month following the request.
Another opportunity occurs during the Annual Enrollment Period (AEP), which takes place every fall from October 15th to December 7th. While changes made during the AEP take effect on January 1st of the following year, a beneficiary can use this time to transition back to Original Medicare.
Moving back to Original Medicare (Parts A and B) allows the beneficiary to apply for a Medigap plan. Since Medicare Advantage often includes prescription drug coverage, the beneficiary returning to Original Medicare will also need to enroll in a stand-alone Medicare Part D plan to maintain pharmaceutical coverage. This ensures the individual does not face a gap in essential coverage.
The Critical Hurdle of Medical Underwriting
Once a person returns to Original Medicare and attempts to purchase a Medigap policy, they face the primary barrier: medical underwriting. This is the process private insurance companies use to evaluate an applicant’s health status, determining whether to accept the application and what premium to charge. The insurer reviews the applicant’s medical history, current health conditions, and prescription drug usage to assess the risk of future claims.
Outside of specific protected enrollment windows, Medigap insurers can legally deny coverage to applicants with pre-existing conditions or charge them significantly higher premiums. For instance, a serious diagnosis such as congestive heart failure, a recent cancer diagnosis, or severe chronic obstructive pulmonary disease (COPD) can be grounds for rejection. This leaves the applicant with only Original Medicare and its potential for high out-of-pocket liability.
The underwriting process involves answering a detailed health questionnaire and authorizing the insurer to review medical records. If accepted, the insurer may impose a waiting period of up to six months before coverage begins for any pre-existing conditions. During this waiting period, the beneficiary may be responsible for the full costs associated with treating that condition. This hurdle is the greatest challenge for most people switching after their initial enrollment period.
When Guaranteed Issue Rights Apply
Certain specific, time-sensitive situations allow beneficiaries to bypass medical underwriting entirely, granting them a “Guaranteed Issue Right” (GI) to purchase a Medigap policy. These federal rights mandate that insurance companies must sell the applicant a Medigap policy, cannot deny coverage due to pre-existing conditions, and cannot charge a higher premium based on health. The most relevant GI rights for a switching beneficiary are often referred to as “trial rights.”
The first trial right applies if an individual enrolls in a Medicare Advantage plan when first eligible for Medicare at age 65, and switches back to Original Medicare within the first 12 months. This allows the person to test the Advantage plan without permanently forfeiting the ability to buy a Medigap policy.
The second trial right applies if a person drops a Medigap policy to try a Medicare Advantage plan for the first time, and then switches back to Original Medicare within that same 12-month period.
GI Rights are also triggered by involuntary loss of coverage, which offers another pathway to switch without underwriting. This occurs if the Medicare Advantage plan leaves the beneficiary’s service area or terminates its contract with Medicare. In these cases, the beneficiary has a protected window, typically 63 days after the coverage ends, to apply for a Medigap policy.
Financial and Coverage Implications of the Switch
A successful switch to Original Medicare plus Medigap results in a fundamental shift in the structure of the beneficiary’s healthcare expenses and access. Medicare Advantage plans often have a low or zero-dollar monthly premium, but require the beneficiary to pay copayments and coinsurance for services up to an annual out-of-pocket maximum. These plans also typically rely on a specific network of doctors and hospitals, and often require referrals for specialists and prior authorization for certain services.
In contrast, Medigap plans require a separate monthly premium in addition to the standard Medicare Part B premium, representing a higher fixed cost. The trade-off is that Medigap policies virtually eliminate variable out-of-pocket costs for Medicare-approved services, resulting in predictable, near-zero expenses at the point of care. With Original Medicare and Medigap, there are no provider networks, allowing the beneficiary to see any doctor or visit any hospital in the country that accepts Medicare. This structure is generally preferred by those who value flexibility, travel frequently, or anticipate high medical usage.