Insurance and billing
Coordination of benefits
Also called COB, dual coverage
The rules for deciding which of two insurance plans pays first and how they share a claim.
Coordination of benefits applies when a patient is covered by more than one plan. The plans use rules to decide which is primary, paying first, and which is secondary, paying part of what remains. The patient should not receive more than the total cost. The office usually bills the primary plan first, then submits the secondary claim with the primary's explanation of benefits. Children with two parents' plans are a common case.
Example at the front desk
She has her own plan and her husband's, so I billed her primary plan first and will send the secondary with the EOB.
US and Canada
In Canada, the Canadian Dental Care Plan has its own coordination of benefits rules for patients who also have private coverage. In the US, the plans' own birthday and primary-plan rules decide the order.