Coordination of benefits

Coordination of benefits is how 2 or more health plans decide who pays first for the same claim. The first plan, called primary, pays up to its limits. The second plan, called secondary, may then pay some or all of what's left.

It comes up when you have your own plan and a spouse's plan, a parent's plan and a job-based plan, or Medicare and other coverage. If the plans are billed in the wrong order, a claim may be denied or delayed.

For example, say a $500 bill goes to your primary plan, which pays $400. Your secondary plan may pay part or all of the $100 left. If it doesn't, you may owe the rest. If a claim went to the wrong plan first, ask the provider to bill your plans in the right order. See insurance didn't pay my medical bill for next steps.