If you have more than one health insurance plan, it can be hard to figure out who will cover your medical bill. When you are covered by two health care plans, there are a lot of rules about which insurance plan pays first and which pays second. This is called coordination of benefits (COB) and mistakes occur often.

Tip: Make sure you tell your doctors about every insurance plan you have.

Follow the rules of the primary insurance

The health insurance that pays first for a service is called the primary insurance. You must follow the rules of the primary insurance if you want them to pay for health care services. If you don’t follow the rules of your primary insurance and they refuse to pay for something, then your secondary insurance will also often refuse to pay.

For example: You go to a doctor’s appointment. This doctor is considered in-network (or approved) by your secondary insurance, but not by your primary insurance. Will any of your insurance plans pay for this appointment?

Answer: No, neither insurance will pay. Your primary insurance won’t pay because you didn’t follow their rules. And, because your primary insurance won’t pay, your secondary insurance also will not pay.

Medicare

Who pays first can be confusing when you have Medicare and another insurance plan.

For example:

If you have Medicare and Medicaid:
Medicare pays first and Medicaid always pays second.

If you have Medicare and a supplemental or medigap plan:
Medicare pays first and the supplemental or medigap plan pays second.

If you have Medicare and COBRA:
Medicare always pays first and COBRA pays second.

If you have Medicare and insurance through your or your spouse’s employer:
It depends on the size of the employer, whether you are 65 or older, and whether you or your spouse are currently employed.

The Medicare.gov – Which Insurance Pays First web page lists many common situations and rules.

Medicaid and Dr. Dynasaur

If you have more than one insurance plan and one of them is Medicaid or Dr. Dynasaur, Medicaid or Dr. Dynasaur will always pay last.