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Regulations & Guidance Administrative Simplification: Coordination of Benefits

Guidance for the coordination of benefits transaction.


Issued by: Centers for Medicare & Medicaid Services (CMS)

Issue Date: August 02, 2020

Under HIPAA, HHS adopted standards for electronic transactions, including for coordination of benefits.

The coordination of benefits transaction is the transmission from any entity to a health plan for the purpose of determining the relative payment responsibilities of a health plan for health care claims or payment information.  See the Coordination of Benefits Transactions Basics.


About Coordination of Benefits

Coordination of benefits (COB) applies to a person who is covered by more than one health plan.

The COB regulations, as well as the HIPAA Privacy Act, permit Medicare to coordinate benefits with other health plans and payers to reduce administrative burden and enable patients to obtain payment of the maximum benefit they are allowed.  The same applies in situations where Medicare is the secondary payer and a provider must file a COB claim to Medicare.

COB claims are those sent to secondary payers with claims adjudication information included from a prior or primary payer (the health plan or payer obligated to pay a claim first). These claims can be sent 1) from provider to payer to payer or 2) from provider to payer.  Additional information about Medicare's COB/claims crossover process is available. 

HIPAA Adopted Standards

In January 2009, HHS adopted Version 5010 of the ASC X12N 837 for coordination of benefits. For more information, see the official ASC X12N website.

For COB pharmacy claim transactions, HHS adopted NCPDP Telecommunications Standard Version D.0. 

These standards apply to all HIPAA-covered entities, health plans, health care clearinghouses, and certain health care providers, not just those who work with Medicare or Medicaid.

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DISCLAIMER: The contents of this database lack the force and effect of law, except as authorized by law (including Medicare Advantage Rate Announcements and Advance Notices) or as specifically incorporated into a contract. The Department may not cite, use, or rely on any guidance that is not posted on the guidance repository, except to establish historical facts.