Coordination of benefits

Coordination of benefits, or COB, is the set of rules that determines which insurance plan pays first when a patient is covered by two dental plans at once: commonly a patient covered under their own employer's plan and also as a dependent on a spouse's plan. The primary plan pays its normal benefit first, and the secondary plan may then cover some or all of the remaining balance, up to its own limits, but only if the claim is filed and coordinated correctly.

Getting COB wrong is a quiet but real source of underpayment and unnecessary patient billing. A claim filed to the wrong plan first, or a secondary claim never filed at all because the front desk didn't realize a second plan existed, both result in the practice collecting less than the patient's actual combined coverage would have paid: money that then either gets written off unnecessarily or billed to the patient in error.

Ask every patient directly about additional coverage at intake and at any insurance change, rather than relying on what happens to be on file, since a missed secondary plan is one of the easier categories of underpayment to prevent with a simple, consistent question.