Answer: Medicare does not submit claims to group medical plans, but they do make demands for reimbursement to correct errors. This usually happens in dual coverage situations, which means that the individual is covered under both the employer’s group plan and Medicare. Federal law then determines which plan must pay first. Generally, the employer’s plan pays first on claims by active employees (and spouses) if the employer’s total workforce size is 100 employees or more. On the other hand, Medicare is the primary payer if the employer has fewer than 20 employees or, regardless of the employer’s size, if the claim is for a retiree or retiree’s spouse. (Further rules apply to employers with 20 – 99 workers, and to special cases involving people with end-stage renal disease.)
To identify potential dual coverage situations, insurers and administrators report group plan enrollment information to the Centers for Medicare and Medicaid Services (CMS). Not all cases are identified in advance, though, and occasionally Medicare pays claims that should have been paid by the group plan. CMS then contacts the employer or insurer to collect information on specific claimants and find possible Medicare overpayments.
CMS usually is looking for information on persons for whom Medicare has already paid claims, which may have been several years ago. Receiving an inquiry now regarding claims paid three years ago is not unusual.
