Coordination of Benefits (COB) is used when a member is covered by more than one health benefits plan. The primary plan is responsible for the initial payment of the claim. The secondary carrier may be responsible for payment after the primary health benefits plan has paid its contracted amount. All provisions of the secondary plan would still apply, such as precertification and referral requirements. If these are not met, the secondary carrier is not responsible for payment of the claim, and the member may be billed for the balance. The combined benefits will not be more than the expenses recognized under these plans.