Coordination of Benefits (COB) is a process used by insurance companies to determine how to cover medical expenses when a person is covered by more than one health plan. COB allows plans that provide health and/or prescription coverage for a person with Medicare to determine their respective payment responsibilities. COB rules determine which plan is primary for you, your spouse, and your dependent children. The primary plan is responsible for processing the claim first and paying its share of the coverage amount, while the secondary plan would then review the claim and pay the remaining balance within its coverage limits.

COB claims are those sent to secondary payers with claims adjudication information included from a prior or primary payer. COB relies on many databases maintained by multiple stakeholders including federal and state programs, plans that offer health insurance and/or prescription coverage, pharmacy networks, and a variety of assistance programs available for special situations or conditions.

COB can be complicated, especially if you and your spouse have different plan types. However, COB rules help organize and manage healthcare benefits and costs. COB applies to various situations, such as when a person has multiple insurance plans, when a baby is added to your policy, or when accidents occur.