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Medicare Compliance/Advanced/30 minutes/Reviewed 2026-07-10

Medicare Secondary Payer and Coordination of Benefits

Determine payer order, collect other-insurance facts, and submit primary adjudication data correctly when Medicare pays second.

Quick answer

Medicare is secondary when federal MSP rules assign primary responsibility to another plan or coverage. Providers must determine payer order before billing and include required primary-payer adjudication information on a secondary claim.

Rules to know

  • Federal MSP rules can override state law and private contract language.
  • Working aged, disability, ESRD, workers' compensation, no-fault, and liability scenarios use different tests.
  • The BCRC develops coverage information; MACs process claims.
  • Primary payer denial or delay facts must be documented accurately.

Operational workflow

  1. 01Ask current coverage and employment questions before service.
  2. 02Determine primary responsibility using the applicable MSP category.
  3. 03Bill the primary payer and retain its adjudication.
  4. 04Submit the Medicare secondary claim with required COB data.
  5. 05Update incorrect coverage records through the appropriate CMS process.

Common failure modes

  • Assuming Medicare is primary because the patient is over 65.
  • Omitting primary payer adjudication information.
  • Calling the BCRC for a claim-processing decision handled by the MAC.

Knowledge check

Who processes Medicare claims for primary or secondary payment?

Official sources

Medicare Secondary PayerCenters for Medicare & Medicaid ServicesReviewed 2026-07-10Medicare Claims Processing Manual (Publication 100-04)Centers for Medicare & Medicaid ServicesReviewed 2026-07-10

Continue this track

IntermediateMedicare Timely Filing: The One-Year RuleIntermediatePrior Authorization Workflow and Denial PreventionAdvancedABNs and GA, GY, GZ, GX Modifiers

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