When Medicare is the primary insurance if a person is an active employee will depend on the employee's age and the employer size. For example, an individual that is over the age of 65 will have Medicare as the primary insurance coverage if their employer has less than 20 employees.
Companies that have over 20 employees are required to offer Medicare recipients the same coverage that is offered to all employees; this coverage must also be offered to covered spouses. In another example, an individual that is under the age of 65 and qualifies for Medicare based on a disability will generally have Medicare as the primary insurance when the employer has less than 100 employees.
One thing that active employees with Medicare should consider is the provider network offered by the employer's health plan. In some cases, Medicare may require that the employee go to an in-network provider in order to receive coverage, and deny payments for out of network providers. This can be true even if Medicare is the primary insurance. Consumers should also be prepared to pay any costs that are not covered by the employer's health plan and Medicare, as there are Medicare approved amounts for certain services.