When a patient has no other insurance coverage besides Medicare, you can be sure that Medicare is that beneficiary's primary payer. But what about when the patient has an additional insurer? You can determine when Medicare is considered the secondary payer and when CMS considers Med-icare primary by accessing a new fact sheet. CMS's "Medicare Secondary Payer Fact Sheet" offers a chart outlining when Medicare pays first and when the program pays second. For in-stance, if a patient has an employer retirement plan and is age 65 or older, then Medicare pays first, and the retiree coverage pays second. On the other hand, if the patient is 65 or older, is covered by a group health plan through his spouse's current employment, and the employer has at least 20 employees, the group health plan pays first and Medicare pays second. Resource: You can untangle other common scenarios using the tool online at http://www.cms.gov/MLNProducts/downloads/MSP_Fact_Sheet.pdf.