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