Often confused with a Medicare lien, a Medicare set-aside is not money Medicare wants back for past bills. A Medicare lien is Medicare's claim for reimbursement after it has already paid for treatment related to an injury. A Medicare set-aside, by contrast, is part of a settlement earmarked to pay for future injury-related medical care that Medicare would otherwise cover.

The purpose is to protect Medicare from paying too soon after a settlement. Instead, a portion of settlement funds is "set aside" and used first for qualifying future treatment tied to the injury. This issue comes up most often in workers' compensation cases, especially when the injured person already receives Medicare or is likely to become eligible soon. In personal injury or liability settlements, set-asides are discussed more cautiously because there is no single federal statute that requires a formal Medicare set-aside in every case.

Practically, a set-aside can affect how much of a settlement is immediately available and how the money must be managed. If it is ignored where Medicare's interests should have been considered, payment for future care can be delayed or denied until the allocated funds are properly spent.

In New York, this can matter in large work-injury settlements, including repetitive-stress or lifting claims from warehouse jobs in Staten Island or the Bronx. In auto cases, it may also arise when a person clears New York's serious injury threshold and settles claims involving substantial future treatment.