Does the secondary insurance always pay the remaining balance?

Does the secondary insurance always pay the remaining balance?

Does the Secondary Insurance Always Pay the Remaining Balance?

It’s a common assumption that secondary insurance will cover whatever the primary insurance doesn’t—but that’s not always the case. While secondary payers do help reduce patient out-of-pocket costs, they don’t automatically pay every remaining balance. Understanding how secondary coverage works can help your billing team set accurate expectations and avoid unnecessary write-offs or patient disputes.

1. The Short Answer: No, Not Always

Secondary insurance does not guarantee full payment of any remaining balance after the primary insurance processes a claim. The amount they pay depends on:

  • The coordination of benefits (COB) rules

  • The secondary payer’s allowable amount for the service

  • What the primary insurance has already paid

  • The patient’s plan coverage and benefits

  • Contractual write-offs or provider network status

2. Common Scenarios Where the Secondary Doesn’t Pay

Here are a few examples of when the secondary insurance may not cover the full leftover balance:

  • Primary payment exceeds the secondary's allowable amount

  • Secondary considers the service non-covered

  • Secondary denies claim due to missing primary EOB

  • Coordination of benefits not correctly filed or out-of-date

  • Patient’s secondary plan has a deductible or coinsurance remaining

  • Provider is out-of-network with the secondary payer

3. How Payers Coordinate Payment Responsibility

Each insurance plan has a contractual allowable for each service. The total payment from both payers combined is usually limited to the lower of the two allowables.

Example:

  • Billed amount: $150

  • Primary allowable: $100, paid $80, patient responsibility $20

  • Secondary allowable: $90

  • Secondary may pay only $10 (to bring total up to their $90 max), not the full $20 balance

4. Patient May Still Owe a Balance

Even with two active insurance policies, the patient can still be responsible for part of the cost. For example:

  • If both plans have deductibles or cost-sharing

  • If the secondary doesn’t cover certain services

  • If COB issues prevent full payment

  • If billing errors cause denial and the claim cannot be corrected in time

It’s important to clearly communicate with patients and review both EOBs before issuing a final balance bill.

5. Best Practices for Accurate Secondary Billing

  • Always verify both insurance plans and COB status at registration

  • Submit the primary EOB with all secondary claims

  • Wait for the secondary EOB before billing the patient

  • Use software that calculates expected secondary payments based on allowables

  • Document and code any write-offs clearly in the patient’s record

Conclusion:

Secondary insurance is a helpful tool for reducing patient financial responsibility—but it doesn’t always pay the remaining balance after the primary insurer. Billing teams should review both plans' allowables, understand COB rules, and educate patients clearly about their potential out-of-pocket costs.


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