Who pays first
Coordination of benefits rules decide which plan is primary. Common examples: an employer plan before Medicare for some working patients, Medicare before a Medigap plan, and Medicare before Medicaid.
Crossovers
Medicare often passes claims automatically to Medigap and Medicaid plans. When it doesn't, you have to bill the secondary yourself, with the primary payer's remittance attached.
Where money gets lost
- Secondary coverage never recorded at registration
- Crossover claims that silently fail
- Small secondary balances written off instead of billed
Ask your biller for a report of secondary balances. It's often an easy win.
This article is general information, not billing, legal or tax advice. Payer rules change; always check current guidance.
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